Paloma tankless takes several tries to fire up

[doxviper]

We have enjoyed our Paloma tankless water heater care free for over 10 years. Recently on occasion it has taken 2 or 3 times turning water off and on again to get the heat going. We get an error code 11 when it fails to ignite. So far it has not failed to ignite after 2 or 3 tries. I've never done any maintenance on it. I did the installation myself along with the electrical changes for high altitude operation. Do these symptoms indicate a course of action I can take to correct the trouble myself?

 

[WorthFlorida]

http://www.palomastore.com/paloma_error_codes.html
http://palomawaterheaters.com/support/

I know nothing about this unit but since error code 11 has something to do with gas ignition I would look into three things. 1) something must sense gas pressure and 2) this is causing the gas valve to remain close or the gas valve is failing to open, or 3) the ignition circuit is failing. The Paloma web site list 11 items to check.
You should call a company that can service it, however Paloma web site has a support page that list some common problems and fixes. If you can get a tech that normally services these units, they’ll usually know what parts generally fail with certain error codes. You don’t want to throw parts at it to see if it fix the problem especially dealing with gas.

 

[Sponsor]

 

[Dana]

A dirty/varnished or defective flame sensor is the most common cause for tankless water heaters to report an ignition failure error. Buffing it up with a plastic scouring pad (eg SkotchBrite) will often "fix" it. Don't use emery cloth, sandpaper, steel wool, or other hard abrasives for cleaning the flame sensor, since that tends make the problem recur quicker.

 

[Plumber69]

A dirty/varnished or defective flame sensor is the most common cause for tankless water heaters to report an ignition failure error. Buffing it up with a plastic scouring pad (eg SkotchBrite) will often "fix" it. Don't use emery cloth, sandpaper, steel wool, or other hard abrasives for cleaning the flame sensor, since that tends make the problem recur quicker.

Its so easy to do, use anything you got to clean it

 

[Tankless Tech]

Try testing the ignitor rod like a spark plug. hold 1/8" away from something metal while the heater attempts to fire. if it does not arc between flame rod and metal then the igniter or ignitor transformer is bad and like they said could just be as simple as cleaning off the flame rod or "flame sensor" or replacing the transformer. if you have had this unit for as long as you say, it is highly likely the burner assembly is clogged with trash ( bugs, insulation, leaves, etc. ) the way you have it vented is a big part in this. Do you have a screen on the combustion air intake and exhaust outlet? if not over time debris could have built up in the burner assembly. i dont have much experience with the model you have but with rheem products i have cleaned the burner assembly out with compressed air and put it back in and it ran like new. the gas comes through the manifold through tiny little holes evenly placed in the burner assembly and over time these little holes get clogged. especially if there is debris getting in somehow.

another aspect is the gas supply. measured in water column. if somehow your regulator went bad or something has failed in gas supply the unit could be drawing too much gas or not enough. if you have a multimeter you can test the gas valve for correct resistance and votage across leads. not familiar with the parameters your particular unit calls for. first thing i like to check is gas supply then move on to check the burner assembly and igniter assembly.

check burner assembly
check flame rod
check igniter
check igniter transformer
make sure venting isnt clogged
check gas supply with a manometer ( use manual to verify desired reading )

 

[Tankless Tech]

its been a couple months since you posted and i am new to this site as of today so i missed your post. i am always interested in feedback coming from consumers in the tankless industry. updates appreciated.