Original message
| fingur
 |  "Blowing Up Control Boards"
, posted Sun 26 Nov 00:15  
Vitals:
Honeywell S8610U1003 control board
RobertShaw 7000DERHC gas valve (LP)
Background:
This is a 600,000btu LP-fired pressure washer burner used in a truck wash. The control board is wired so that it is a standing pilot, rather than intermittent ignition (24vac constant to TH-W). The main valve is controlled by devices wired in series (flow switch, high-limit, thermostat, etc). We have used this arrangement for years with no trouble.
Problem:
After complaint of no heat, checked operation. Cycled power to unit. No response whatsoever (i.e., no spark, no power at PV terminal on control board). Verified transformer output, stable at 27.1 VAC. Pulled pilot assembly and inspected flame sensor and ignitor. Cleaned and reinstalled, still no response. Verified wiring correct.
Everything looked OK, so I replaced the control board with a new unit. Upon power-up, the pilot solonoid clicked once - no spark was ever detected. After that initial click the new board exhibited the same symptoms as the old board. Installed both boards in a working system with no results, both boards are definately faulty.
Any suggestions on how to pursue this? I need this burner back online as soon as possible, but I can't afford to keep throwing boards in. Is it possible that the valve itself could short to ground and take the board out? Any ideas are appreciated!
Thank You!
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Replies:
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| Zzz
| "Re(1):Blowing Up Control Boards" , posted Fri 8 Dec 01:16
This is my second time reading your post and still I am wondering why if you have a standing pilot you have a board, you don't need it. Let the pilot keep the valve open and go through the safteys to get the main valve open. IDF can run on a relay if there is one.
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| shortys
| "Re(1):Blowing Up Control Boards" , posted Sun 26 Nov 13:14
It sounds like the pilot valve may be bad. You might try shutting gas off and wiring pilot valve direct. Check amp draw. The max rating of the controller pilot valve contact is 1 amp. Also make sure no wire is pinched or grounded.
"Short on price Long on quality." shortyshvac.com
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