Aquastat easy fix

Homesteader

Everything can be working on a gas fired boiler except that the radiators are not getting hot.  The Honeywell Aquastat can be doing everything correctly except providing 120v to the circulator pump due to a broken solder joint on the aquastat’s circuit board.  New units are almost $300, but can be revived by exposing the backside of the circuit board, finding the pitted solder joint and reconnecting the joint by “re-flowing” the solder with a soldering iron and a bit of solder.  Once re-soldered, the aquastat can power up the circulator pump again.  No expense , simple, effective:

109A_5

Hello @Homesteader,
Yes it is a very easy fix if you have the tools and the skills, try to get a HVAC/R service Pro to do that for you. Electronic Technicians do it every day and they don't complain about UL listing violations or other issues.
You can make the solder joint even more robust by removing the old solder, cleaning the component's pin (usually a relay in this case) and scraping away some of the solder mask (if needed) and rap each pin tightly with 18 Ga. copper wire (a turn or two) and bring the two ends of the 18 Ga. wire back over the circuit board foil at least 3/8" inch and solder the whole thing.
In the case of the Aquastat, do this on each pin of the relay while you are there. Inspect for other solder joints that look like they are on their way to failure.
In some cases Furnace control boards can also be easily repaired too.
For another example this board is back in service.

HomerJSmith

I've been talking about this for years. The problem is liability issues for a tech to do this.

Remember, there a high voltages and low voltages which are separated with fish paper as required by the NEC. You want to make sure that the capillary tube doesn't touch a high voltage point when putting it all together or ZAP!

109A_5

HomerJSmith said:

I've been talking about this for years. The problem is liability issues for a tech to do this.

So the liability issues are magically gone with every other electrical / electronic device in the home that gets repaired to the component level or just a bad connection ?

Basically the OEM should have the liability for a poor design.

Homesteader

109A_5 said:

Hello @Homesteader, Yes it is a very easy fix if you have the tools and the skills, try to get a HVAC/R service Pro to do that for you. Electronic Technicians do it every day and they don't complain about UL listing violations or other issues. You can make the solder joint even more robust by removing the old solder, cleaning the component's pin (usually a relay in this case) and scraping away some of the solder mask (if needed) and rap each pin tightly with 18 Ga. copper wire (a turn or two) and bring the two ends of the 18 Ga. wire back over the circuit board foil at least 3/8" inch and solder the whole thing. In the case of the Aquastat, do this on each pin of the relay….”

109A_5 

I like those suggestions, the solder joint I achieved without disconnecting wires and just enough space for the tip of the hot soldering iron to reach the bad pin , wasn’t as stout as I’d have liked , when it eventually fails, I’ll do the wire wrap trick. 

Thanks!