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Water Heaters

Eccotemp FVI12-LP
Tankless Water Heater
Review

by Vaughn Aubuchon

I recently had an Eccotemp tankless water heater installed. I'm afraid that there were a few surprises. Below, I have compared a standard water heater with a tankless water heater.

Allegedly, there are significant money savings when using a tankless water heater. However, NO AMOUNT of savings is going to justify non-functionality.

1. FVI12 Quick Summary

2.
TWH Comparison

3.
FVI12 Control Settings

4.
FVI12 Specs

5.
FVI12 Hysteresis

6.
Heating Threshold vs. Flow Rate

7.
Reducing Flow Rate Increases Temperature

8.
Other Tankless Water Heaters

9. Takagi Propane TWH List

10.
Rinnai Propane TWH List

300

30


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1. FVI12-LP Quick
Summary

The FVI12-LP is an unsophisticated, poorly performing unit. Here's why -

1. It contains some electronics, but NO COMPUTER to control the output water temperature, which CANNOT be regulated. Unlike other TWH units.

2. On VIABLE TWHs (Tankless Water Heaters), you SET the temperature, and the heating adjusts to the demand, so that the output water temperature remains constant.

3. On this FVI12 TWH, you set the absolute amount of gas, and the temperature varies like crazy, as demand changes. This is a cheap, poor design. If you are taking a shower, make certain that no one tries to wash the dishes, or you will be zapped with cold water.

4. After the hot water is turned on, the flow is gradually reduced to the point (1.5 GPM) where heating is TURNED OFF COMPLETELY. A great thrill when showering.
One solution to this is to turn on the hot water in the sink, as well as the shower, which insures adequate flow to maintain heating.
Another solution is to turn on the shower WAY HIGH, far more than normal. Make sure your shower head is not clogged, even partially. The problem with this is, if you have a slow drain (me), you will be standing in a puddle of water before you finish your shower.

5. FORGET ABOUT A LOW-FLOW SHOWER HEAD - YOU WILL NEVER SEE ANY HOT WATER DUE TO INADEQUATE FLOW. At energy.gov, it states "For maximum water efficiency, purchase aerators that have flow rates of no more than 1.0 gpm." At this flow rate, the Eccotemp FVI12-LP will NEVER heat ANY water, ever.

6. To help make this particular TWH work, set the temperature on the control box to the same temperature you like your shower. I like 106°F (hot-tub temperature). That way, you don't have to turn on your cold water at all, which maximizes hot water flow, and minimizes total water flow.


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2. Tankless Water Heater
Comparison
Product Features

#
Issue
Regular
Water Heater
FVI12-LP
TANKLESS
Water Heater
1
Temp.
Control
Perfect
Problematic
2
# of
Controls
1
2

Easy as pie with a standard water heater. WHOLLY inadequate instructions for setting the tankless water heater, using the "Gas Regulator" control and the "Water Temperature Regulator" control.

3
Min.
flow rate
to START heating

Unspecified
Not an issue
1.5 GPM

In the Eccotemp FVI-12 online PDF manual, on page 25, it says
"Notice: The water heater MAY NOT OPERATE with a small water flow**. In such (a) case, increase the water flow. If water heater still does not operate and (the) hot water faucet is completely open, increase the temperature setting on the control panel."

This is another one of those stupid "MAY" happen statements. PURE BS. It should read "will DEFINITELY NOT operate." The parameter "min. flow rate to START heating" should be SPECIFIED.

** Please note that "small water flow" defined here is ONE-HALF the maximum capacity of the unit (1.5 GPM vs. 3.0 GPM.) According to Consumer Reports, "The flow must be fast enough, typically a half-gallon per minute, to turn on the sensor." Eccotemp disagrees. The FVI12-LP has a turn-on level of 3 times that, or 1.5 GPM.

4
Min. flow rate to MAINTAIN heating
Not an issue
1.00 GPM

Even after you get heating to begin, another parameter needs to be specified. -->
The parameter "min. flow rate to MAINTAIN heating" should be SPECIFIED. As pipes heat up, flow is reduced. In extreme cases, such as mine, at a certain point, heating is turned off.

Bottom Line

So, if you just want a little water to brush your teeth, or wash your hands, it is not very practical. The Eccotemp will not heat unless you blast it. This is an inconvenience to most people.

20

80

200

200 - 500


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3. FVI12 Control Settings

Eccotemp tankless water heater control panel

1. The black marks on the knobs indicate the approximate proper control knob operating positions. The Gas Regulator is set to "High", which allows for varying gas usage, based upon demand. If it is set to "Low", precious little water can be heated.

The grey knob positions which I drew in indicate the approximate full range of each control. The arbitrary position of the little "curved boxes" gives you little hint of knob range. A "full-scale" dial should be used, with corresponding numbers, even though they are not absolute or calibrated. A control dial without increments is just plain foolishness.

2. After installation, my knobs were not set as shown. The right-hand Water-Temperature knob was turned up high (RED mark), and the left-hand Gas Regulator knob was used to set the temperature at 110°F (RED mark). This worked fine at ONE faucet, and ONE flow rate, except for continually falling temperature and limited flow rate.

However, as demand increased (turned on washing machine), insufficient gas flow caused auto-shutdown. Not only did the water temperature drop, but the flow rate was also reduced to a trickle, resulting in unacceptable performance.

3. I fixed this by turning the "Gas Regulator" control knob up to midlevel from low level. This allowed sufficient gas delivery to heat the water during increased flow. I then lowered the temperature to 110°F using the "Water Temperature Regulator" knob. This seems to have improved the situation.

4. A great deal of time can be saved by reading the "Basic Information" found on page 1
of the
"FVI12-LP Troubleshooting Guide" -

Basic Information:
"The FVI12 is manually controlled, meaning that it always uses the exact amount of gas you set it to and reduces water flow by the amount you set it to. Because it operates in this manner, a faucet with low water flow will run at a higher temperature than a faucet with a higher volume of water flow. The FVI12 cannot be set to maintain an exact temperature regardless of which fixture you use. If your water flow varies between fixtures or if it is changed while the water heater is in operation, the temperature will change accordingly. Please keep this in mind."

IN OTHER WORDS, the temp of the heated water is determined by the demand (Water Flow Rate). This is NOT DISCUSSED in the 26-page "Use and Care Manual", WHERE IT SHOULD BE ON PAGE 1, so you can get some clue as to what is going on with this unit.



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4. Eccotemp FVI12-LP
Tankless Water Heater
Specs
Product Installation

#
Subject
Parameter

.
Notes

1

Brand

Eccotemp

Made in China, Office in N. Carolina

2

Model

FVI12-LP

Liquid propane model - Click here for the Owner's Manual from Eccotemp.

3

BTU

74,500 BTU Max

Some places 74,000 BTU

4

Max Del. Rate

3.6 gallons/ minute

Some places say 3.0 GPM, some places say 3.4 GPM

5

Min Del. Rate

1.5 GPM

1.5 GPM Minimum to begin heating water
THIS MUST BE SPECIFIED. IT IS NOT.
THIS IS DECEPTION, PERIOD. IT IS THE BIGGEST PROBLEM WITH THE UNIT.

6

Min. H2O Pressure

32 PSI

Some say 35 PSI is required - Only 15 PSI is needed for most other TWH units

7

Install Date

Oct. 12, 2012

Test Date - Nov. 16, 2012
TOTAL FAILURE - Nov. 30, 2012
Water will NOT heat, at all, under ANY circumstances.
It worked, with constant attention, for 1 1/2 months.

8

Price

$ 269 (most vendors)
$ 339
Factory List

-

9

Documen-tation

Use and Care Manual
AKA "User's Manual"

FVI-12.pdf - NOT text-based, cannot be searched, enlarging does NOT improve quality - 30 pages - terrible quality.

Installation Guide

Not available online - They obviously don't want you to see it, unless absolutely necessary - it does NOT instill confidence.

Troubleshooting Guide

FVI12TroubleshootingGuide.pdf - 8 pages

10

Suppliers

buyplumbing.net

-

11

Reviews

Amazon FVI12-LP reviews

-

40

60

120

200 - 450

40



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5. Eccotemp FVI12-LP
Tankless Water Heater
Hysteresis
How Demand (Flow) Affects Heating
Why There Is NO HEAT at Low Flow

Flow
Rate #
Timer
Seconds to Fill One Gallon
FLOW
RATE
Gallons
per
Minute
GPM
Condition

.
Notes
(data taken by me)

1
60
1.00

Slowest flow

Heat off (increase flow to turn heat on)

2
48
1.20

Slow flow

Heat off

3
43
1.39

Faster flow

Heat off

4
41
1.47

Faster flow

HEAT ON (flow required to turn heat on)

5
37
1.61

Faster flow

HEAT ON (decrease flow to turn heat off)

6
44
1.37

Slower flow

HEAT ON

7
48
1.20

Slower flow

HEAT ON

8
53
1.14

Slower flow

HEAT ON (flow required to MAINTAIN heating)

9
59
1.02

Slower flow

Heat off (increase flow to turn heat on again)

10
49
1.22

Faster flow

Heat off

11
43
1.39

Faster flow

Heat off

12
40
1.49

Faster flow

HEAT ON

-

The flow rate was slowly increased from zero, by the increments shown. At a flow rate of 1.47 GPM, the water started heating. The flow rate was then decreased until the flow rate was 1.02 GPM, when the heater turned off. Increasing the flow rate again resulted in the heater restarting at 1.49 GPM.

Nov. 17, 2012

Turned on kitchen hot water full blast - heat would not turn on.
Turned on bathroom hot water full blast - heat would not turn on.
Turned on BOTH kitchen and bathroom - Kitchen water heated to 105°F.
Bathroom water temp was heated to 85°F.
Turned off bathroom hot water, kitchen water temp went up to 126°F.

40

60

60

100

340 - 640



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6. FVI12-LP
Water Temp vs. Flow Rate

.
<----- Flow Rate Range ----->
0 - 1 GPM
.
Hysteresis Area
1 to 1.5 GPM
1.5 to 3.0 GPM
Cold Water
(not enough flow for heat to
turn on, or to STAY on)

Cold water if you are ramping up.

HOT Water
(3.0 GPM is the maximum hot water
flow rate specified)

Hot water if you are ramping down.

^This is the flow rate I want.

200

100

300 - 600

The Eccotemp FVI12 needs a flow rate of 1.5 GPM to START heating water,
and it needs a flow rate of 1.0 GPM to MAINTAIN water heating.

MOST Other TWH
Water Temp vs. Flow Rate

.
<----- Flow Rate Range ----->
0 - 0.5 GPM
.
0.5 to 3.0 GPM
Cold Water
(not enough flow for heat to turn on, or to STAY on)
HOT Water
(4.0 GPM is the maximum hot water
flow rate specified)

100

500 - 600

According to Consumer Reports, "The flow must be fast enough, typically a half-gallon per minute, to turn on the sensor."
Rinnai and Tagaki are typically 0.4 GPM minimum flow rate.

40

60

60

100

340 - 640



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8. Other Tankless
Water Heaters

A friend of mine who lives in the Sierra foothills has 2 installed tankless propane water heaters, and loves them both, due to the fact that THEY WORK. Here is the rub - they were quite expensive.

BRAND

MODEL #

BTU

MIN.
WATER
PSI
REQUIRED

MINIMUM
ACTIVATION
RATE

PRICE

TOTAL
NUMBER OF
MODELS

Rinnai

R75LSi-LP*

NO SPECS

NO SPECS

0.4 GPM

$ 1,297

4 Ultra
4 Luxury
5 Value

Takagi

nnnnn**

-

15 PSI

NOT specified

$ 850

16 major
(? propane)

Eccotemp

FVI12-LP***

74,000

30 PSI****

1.5 GPM actual
Unspecified

$ 339
(List)

9
(1 propane)


*

NOTES:
This Model # is NOT listed on the website.
Rennai website general part numbers are ALL different from specific models listed online.
Website part numbers all start with U, L and V. Everywhere else, they start with R.
This is SCREWED UP! Could not be worse if they planned it!
There is no "key" to part number designations - YOU must figure it out.
You MUST go to a dealer for quote - markups vary widely. NO "list" pricing.
You cannot list "propane water heaters" on website - You must slosh through them all.

**

This Model # is NOT listed on the website.
Takagi website general part numbers are ALL different from specific models listed online.
Website has NO search function - you cannot search for "propane".
There is no "key" to part number designations - YOU must figure it out.
You MUST go to a dealer for quote - markups vary widely. NO "list" pricing.
You cannot list "propane water heaters" on website - You must slosh through them all.

***

Flow rate issues, activation issues, specification issues.
Eccotemp website offers NO SPECIFICATIONS AT ALL.
There is NO SPEC SHEET!!!
Instead, you are referred to an inadequate, inconsistent PDF written in Chinglish, which will frustrate the pants right off of you. Eccotemp gets credit for putting the LP in the part number - Liquid Propane.

****

This info is available ONLY in the "Troubleshooting Guide". That's right. When your spec is TERRIBLE, hide it.

70

100 - 550

50

90

90

60

90



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9. Takagi Propane
Tankless Water Heaters
Factory Part Numbers vs. Retail Part Numbers
Takagi
Web
Site
#
FACTORY
Part
Numbers
.
RETAIL
Part
Numbers
Propane
BTU
Min.
Flow
Rate
GPM
Cap.
GPM

Example
Amazon Price

1
T-KJr
T-KJr-LP
140 K
no
spec
3.8

$ 665

2
T-KJr2-IN/OS
T-KJr2-IN-LP
140 K
no
spec
6.6

$ 656

T-KJr2-OS-LP

$ 625

3
T-K4-IN/OS
T-K4-OS-LP
190 K
no
spec
8.0

$ 822

T-K4-IN-LP

$ 864

T-K4-OS-LP

$ 859

4
T-K3
T-K3-OS-LP
199 K
0.4
7.0

$ 857

5
T-D2-IN/OS
T-D2-IN-LP
199 K
no
spec
10.0

$ 1,057

T-D2-OS-LP

$ 1,051

T-D2-OS

$ 1,066

6
T-K3-Pro
none
199 K
no
spec
7.0

-

7
T-H2S
none
180 K
no
spec
8.0

-

8
T-H2
T-H2-DV
199 K
no
spec
9.0

$ 1,280

T-H2-OS-LP

$ 1,310

T-H2-DV-LP

$ 1,256

T-H2S-DV-LP

$ 1,225

9
T-M32
T-M32-LP
240 K
0.4
9.0

$1,592

T-M32-ASME-LP

$ 1,922

10
T-M50
T-M50-LP
380 K
0.4
14.5

$ 3,277

T-M50-ASME-LP

$ 3,613

11
T-H3-DV/OS
none
199 K
0.4
10.0

-

12
T-H3S-DV/OS
none
180 K
0.4
8.0

-

13
T-H3J-DV/OS
none
160 K
0.4
6.6

-

14
T-KJr2U
none
140 K
0.4
6.6

NG only
TBGSS01212.pdf

15
T-K4U
none
190 K
0.4
8.0
16
T-D2U
none
199 K
0.4
10.0

none
T-M199-LP
199 K
0.75
9.6

$ 1,396

none
T-T-KJr-OS-LP

??

??

??

$ 618

"Commercial"

NO Spec Summary - must open every PDF data sheet.
Some file numbers have ZERO relationship to the part number - i.e., TRGSS01512.pdf = T-H3. T-H3J, T-H3S

"Residential"

Not in product guide

J = 160 K, 6.6 GPM
N= Natural gas
OS = Outside
P= Propane
S = 180 K, 8.0 GPM

-

40

100

120 - 500

40

40

40

110

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Takagi TWH
Part Number Key

KEY
DV = Direct Vent
DV = Outside
H = Condensing
Jr = Junior (or "J")
K = Residential
M = Mobius
T = Takagi
U = Ultra low NOx

ASME = American Society of Mechanical Engineers

DV = Direct Vent
IN = Inside
OS = Outside
LP = Liquid Propane (some places -P)
NG = Natural Gas (some places -N)

140

310 - 450


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10. Rinnai Propane
Tankless Water Heater
Summary
Factory Part Numbers vs.
Retail Part Numbers

Rinnai
Web
Site
#
FACTORY
Part
Numbers
RETAIL
Part
Numbers
REU-xxx-US
Propane
BTU
Min.
Flow
Rate
GPM
Cap.
GPM

Value Series

1
V53e
VAM-1620-W
120 K
0.6
5.6
2
V65e
VC-2025-W
150 K
0.4
6.6

3
V65i
VC-2025-FFU
150 K
0.4
6.6

4
V75e
VC-2528-W
180 K
0.4
7.5
5
V75i
VC-2528-FFU
180 K
0.4
7.5

Luxury Series

1
RL75e
VC-2528-WD
180 K
0.4
7.5
2
RL75i
VC-2528-FFUD
180 K
0.4
7.5

3
RL94e
VC-2837-WD
199 K
0.4
9.8

4
RL94i
VC-2837-FFUD
199 K
0.4
9.8

Ultra Series

1
RU80e
KB-2530-WD
152 K
0.4
8.0
2
RU80i
KB-2530-FFUD
152 K
0.4
8.0
3
RU98e
KB-3237-WD
199 K
0.4
9.8
4
RU98i
KB-3237-FFUD
199 K
0.4
9.8

e = W = ??

-

i = FFUD = ??

50

80

120 - 450

50

50

50

50



Why Did I Create This
Takagi/ Rinnai TWH Summary?

The Takagi online "Product Guide" is very difficult to read.
When magnified, one can no longer view the entire page. No proofreading here.

Part numbering
Takagi part numbering is very inconsistent - no key is offered.
Typically, there are 3 dashes, which may be present, partially present, or TOTALLY absent.
Superfluous spaces may be added.

There is NO APPARENT order to the part numbers listed at Takagi.com - vaguely by price.
The designator "LP" may be missing, as in Model T-D2-OS.

ALL well-conceived part numbers should have maximum information embedded.
ALL part numbers should BE CONSISTENT, and adhere to a template.
There should be a key, which is NOT violated.
ALL part numbers should BE THE SAME, NOT xx33 in one place, and yy44 elsewhere.
Using different part numbers in different instances is clumsy and confusing, or perhaps even worse, intentionally deceptive. Sales suffer, because people don't like confusion, or double-talk.

Specifications
So-called Amazon "specs" are abysmal - they don't exist - not even capacity or BTU.
WHERE ARE all the Amazon reviews? Nonexistent. Very strange. Due to low sales?

Some units are listed as "Residential", some "Commercial", and some, BOTH,
thereby rendering the designations meaningless.

On several spec sheets, instead of listing Min.=15 PSI and Max.=150 PSI, Takagi lists
Max.=150 PSI and Max.=150 PSI, when the REAL issue is the Minimum. No proofreading here.

"Flow" is NOT listed under "Specifications". HUH? You must download the PDF "Specification Sheet". PITA.

Japanese Documentation

Having worked for several Japanese IC companies, 2 things are clear -
1. They make great products. Their quality control is second to none.
2. They fall down when it comes to documentation. Why?
   a. They don't acknowledge the importance of excellent, error-free documentation.
   b. The writers are NOT native English speakers
       ("good enough", seems to be the mantra).
   c. No one who IS a native English speaker proofreads and makes necessary edits.
   d. The writers may not be engineers - another reason for confusion.
   e. "Vague" is less confrontational, and more polite, than specificity.
       We don't want "polite" here. Or obfuscation by omission.
       Residential? Commercial? "Could be meat, might be cake." ... George Carlin
   f. They are slow to update website documentation.
       Are omitted models very old, or very new? How are we supposed to know?
   g. What is "adequate" for them, may not be so adequate for discerning sophisticated customers.



Disclaimer: This is a review of the Eccotemp Tankless Water Heater Model # FVI28-LP.
I have no relationship with ANY Tankless Water Heater maker.
Please report any errors that you may find.

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Review was last updated on 2015-03-06.