Aquavac 42 tankless water heater: we cannot find a source for parts in US. Please help

1) No.
NO.
Do NOT store combustibles close to a water heater, fireplace, or any source of ignition, including HVAC, space heater, microwave, appliance, etc.
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html#bang

2) Tankless water heaters do not have FVIR safety features found in tank-type gas water heaters rated less than 60,000 BTU.

3) Tankless water heaters draw large amounts of air into combustion chamber from surrounding room, and this air feeds directly into the burner flame with no barrier.

4) If flammable vapors enter tankless, then it can cause fire, explosion, conflagration.

5) Read product manual and safe a life.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

1) Type and brand water heater unknown.
Copy following link for Rheem-Richmond tankless error codes:
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

2) Question posted under Richmond tank-type power vent.
Error code 24 appears to be Rheem-Richmond tankless water heater.

3) Add a comment with more information about type, brand, age of water heater including what you have tried so far.

4) Call service technician to catch up on required yearly maintenance.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

11-2-12
Copy following links for Rheem tankless error code 11, and other useful resources.
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
http://waterheatertimer.org/pdf/Tankless-error-code-11.pdf

Repair tankless water heater, any brand, same day, yourself for around $350 by replacing 1 part > the whole thing.
http://waterheatertimer.org/How-to-install-gas-water-heater.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

3" category III stainless for special venting

Tanklessking shows Category III stainless steel vent kit for this model
3" vent
http://tanklessonline.com/rheem-water-heaters-RTG42.html

ptg-42-pvn has minimum 31,000BTU and max 118,000BTU
Max water temperature 120 degrees F
Spec sheet says: 3" special venting
http://www.palomatankless.com/products/42/specifications.html

Hart and cooley show special vent 3" stainless thru-the-wall vent
http://www.hartandcooley.com/specialgasvent/PDF/851515%20Tankless%20Water%20Heater%20Installation%20Vent%20Kits%20sell%20sheet%20-%20HC%20-%20low%20res.pdf

Hot water sources shows thru-wall or thru-roof
http://www.hotwatersource.com/RTG42PVN-Rheem-Indoor-Natural-Gas-Tankless-Water-Heater/RTG42PVN,default,pd.html

http://waterheatertimer.org/pdf/Tankless-roof-vent-installation.pdf

Usually when a part has build-up that signals part replacement.
I am concerned with condition of other parts, since build-up occurs in more than one place.
Replacing one part is no guarantee that problem will be solved, and just as likely the new part will cause unit not to work.

If you have Tankless, then open following link for troubleshoot resources before you call service technician:
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

Tankless cannot be exposed to water with more than 11 grains hardness or they will stop working.
Tankless must be delimed and maintained yearly.
Deliming will not restore efficiency to tankless water heater exposed to hard water and mineral build-up. Water softener and filter are required, and these things can reduce water flow and pressure that will cause low pressure and flow that will stop burner from activating.
Water temperatures above 135 can cause minerals to dissolve out of water and coat metal surfaces.
Read manual for troubleshooting and yearly maintenance requirements.

Tankless problems are like bowling on a ship.
Repair most tankless problems yourself, same day, any brand, for around $330.
http://waterheatertimer.org/How-to-install-gas-water-heater.html

Upvote the help.
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

Before calling service technician, open following link for troubleshoot resources:
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

The same error code and problem on one person's tankless unit can have different solution than another tankless unit.
This is because tankless require perfect operation of parts and sensors while being affected by incomming water and gas issues, and venting, plus plumbing factors.
Replacing one part is not always the fix, since that part interrelates with so many other parts, each affected by the operation of the other, and operation of the chip and integrity of wiring and wiring connections.

Read manual for yearly maintenance requirements, and calculate those costs when figuring anticipated $1-8 monthly energy savings from owning tankless.
Check that your region has reasonably-priced, qualified service technician for your brand before buying tankless. And check part list and cost of parts before buying any water heater because these factors weigh-in after a few years of operation.

Repair most tankless problems yourself, same day, any brand, for around $330.
http://waterheatertimer.org/How-to-install-gas-water-heater.html

Upvote the help.
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

I could see how it might not work in parallel. Much water would go thru the conventional heater, so there would be low flow thru the tankless.
Now, the tankless is getting hot water from the conventional. Try shutting the conventional heater's power source off so the water gets cold, then see what happens with the tankless.
Gary

When a tankless is installed, they are usually set up with a recirc. Theis keeps the water continuously heating to some degree.
When a tankless is installed into a home it has nothing to heat the water that is sitting in the pipe from its faucet to its heat source. Now as soon as you turn on the faucet, you have to let all that cold water run out until the newly heated water comes out from when you started the faucet.
You could measure the volume until heat and it will be pretty much the same every time for a given faucet.

The fact that your faucets are low flo is only part of the factor involving time it takes to get hot water. Another factor is volume. The diameter of your pipes makes a difference. You can remove the low flo restrictor from the faucet farthest away to speed up the process at least a little.

http://www.boschhotwater.com/Portals/7/TechBulletins/TWH-G1-08_Pilot_flame_no_burner_flame_troubleshooting.pdf

Here is the service bulletin for that problem.

Gary

Laing UCT-909-TANKLESS UltraCirc Tankless Water Recirculating Pump

This is designed to maintain the proper flow to fire the heater. Please be sure the pressure in the house is at least 5 psi over the minimum required for your unit.