Heater Question

[Sully]

Sounds like a possible water flow problem.

[waste]

Larry, if you have the owner's manual for the unit, I'll wager that you can handle this yourself. (As I understand it, " (a)Qualified service person" is one who can turn a wrench and read the manual - I got certified 13 (+/-) yrs ago at a trade show - we looked at the heater and recieved the trouble shooting guide and a week later had a nice certificate (suitable for framing) saying that we were factory authorized to work on them) Now these were the old 'dumb' microvolt units, but it should be the same set-up. The computer is telling you what the problem (probably) is, however it's always nice to double check before replacing parts.
What you want to do is determine where the hi- limit switch is (the manual should tell you - it should have a trouble shooting section in the back (* if you can't understand a word of it, flip the manual over to see the English side ). Once you know where the swich is, TURN THE HEATER OFF and take a peice of wire to 'jump'/ bypass the switch and turn the unit back on (turn the thermostat to it's max to be sure that you have a 'heat demand') so the heater will try to fire. If the heater fires and runs with no other problems, replace the hi-limit switch.
There is a chance that there is a problem with either the 'fenwall' (firing control wall - it's gotta be a Brit term) or the control board and it's showing a 'hi-limit' problem as default, that's why 'jumping' the switch is a good idea BEFORE buying a new one. If it turns out to be the fenwall or control board, please post back as there is some further info I will share with you.
I wish you well with this and if I can be of further help, let me know and I'll do what I can from afar - Waste

[halefmly]

Waste,

Thanks for the encouraging advice. I have located the set of three hi-limit switches on the owners manual schematic. I also learned that I have a two-year warranty, so I think I'll take the easy route and call the PB tomorrow to get the warranty service. Beats breaking something else and having to get a new heater.

If the problem continues to reccur after the warranty expires, I'll be asking more questions in the forum.