Two thermopiles???

[blk]

Went to a no heat call on a Majestic Direct Vent unit today,sorry never wrote down model/serial#, were the pilot would not stay lit. Now here's were things got interesting, unit had 2 thermopiles wired into a cicuit board on the bottom of a I believe to be a Robertshaw Control Valve? Homeowner had no manual or scemeatic for this unit,so I was wondering what the purpose of the 2 thermopiles is, are they in series to the board to provide extra millivolts to operate valve thru circuit board? It appears that the cicuit board was bad as there was no LED light "ON" while trying to light pilot. Shutting valve off then on again to try to reset board did nothing. Customer is to call installer back out to check unit, as I was unsure how to properly trouble-shoot this particular unit, it was the first one of this nature I have seen to date and besides, working for the local utility, we carry no parts other than thermopiles. I'm curious how this system works???

[mike3]

Are you sure it wasn't a Sit Valve?
Take a look here: Page 13
http://www.kingsmanind.com/pdfs/manuals/5000-P951CP.pdf

[blk]

It may very well have been a SIT valve Mike ,although it did not look like that on page 13. It had no thermocouple, just the 2 thermopiles and the piezo unit, and it also had a remote control.It did not look like the circuit board on the bottom of the valve could be removed without pulling the valve and may even come as a complete unit?

[natgastech]

It is a RFN unit (remote controlled valve and fan all in one). The last one I worked on had an intermitten short on 1 of the piles which made me look at the valve. Do yourself a favour and replace both thermopiles before the valve.

[jtp10181]

Didn't honeywell make some sort of a crazy valve that had an integrated remote? That sounds like what you may have been looking at.

[blk]

There was a small LED light at the front btm right side of the valve on the circiut board which even after manually holding pilot on for several minutes would not come on and pilot would drop out immediately after releasing knob. Yes the units fan was wired into the board in the back.Sorry for the lack of info guys, I just didn't spend alot of time on the call as we don't replace parts, but I am very curious as to how this system operates. Is there a web site I could find a wiring diagram for one of these systems?

[hearthman]

Honeywell RV8310E 1000mv system. No thermocouple. Need min. 500mv each TP open circuit. Polarity important-- white wires to the white dots on the connectors.

See their Gas Hearth Product Service Manual for complete details.

HTH

[blk]

Thanks Hearthman, good tip on the polarity issue, can honestly say I don't recall the orientation of the white wires, but did have over 600mv open cicuit on both thermopiles. Customer is to call me after service co checks unit and tell me what they find wrong with unit. I'm fairly confident the circuit board is the culprit!