Raypak heater short cyclIng

[bryankloos]

Hi all,
I have a raypak 336.

It's about 5 years old and never had a problem.

I tried to fire up my heater yesterday, started time pilot with no problems.

When I turned up the thermostat the burner would ignite and run for about 20 seconds and then turn off. 15 seconds later it would ignite again and burn for 20 seconds and turn off.

I'm assuming it's a safety switch, pressure or temp that is acting up. That said do any of ou have an idea what to look for before I start pulling things apart?

Thanks

Bryan

 

[ps0303]

Sounds like it not recognizing that the unit lit.

5 years old, doesn't it have a digital display on it?

 

[freon]

Sometimes the pilot tube or orifice for the pilot can start to crust up. When the pilot is only lit, there is enough pressure to keep the power pile heated up enough to keep the valve on. Once the main gas light the pilot gas may lose pressure now due to a partial clog and not keep the power pile hot enough to keep the valve open.

See if you can still see a strong pilot once the main valve lights.

 

[freon]

Also you didn't say, is this a standing pilot, or electronic ignition ?

 

[freon]

if its electronic ignition, your flame sensor is dirty. its a metal rod with only one wire attatched to it and the pilot flame touches it. needs cleaned with steel wool or wire brush NOT sandpaper.

 

[Pool Clown]

Raypaks "flame sensor" is integrated into the pilot hood. If it is cycling, you're more than likely having an over-temp issue. Either the AGS (135 degree) or the Hi Limit (140) is opening, then resets once the heater shuts off and cools. Then the heater begins its "call for heat" cycle again. Note: These two switches are probably NOT the problem but rather just doing their job(s). IOW, the switches opening are the symptom of this problem and not the cause. If the heater is 5 years, i would look at sooting of the exchanger, which would point to poor ventilation, both combustion AND makeup air. Your heater is not exempt from these problems even if the heater is out in the open. If your heater is in a high wind location or if your equipment is enclosed on all four sides with no roof. Those problems could take 5 years to develop. Another problem could be water chemistry related. If, for whatever reason the exchanger tubes on the water side become blocked off by calcium build up, that would cause a over-temp cycling. That problem can develop sooner.