New to ODB's and I can't get the circulating pump to come on when thermostat calls for heat. I have a second thermostat that just turn the HVAC fan on and the circulating pump on. The pump will run. We jumped it out to fill lines before stayrt up. Any opinions will be appreciated.
H2 Troubleshooting
- Thread starter Hud101
- Start date
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hondaracer2oo4
Feeling the Heat
Need more info about how your system is plumbed. The vast majority have the pumps run 24/7 for one thing. How are you powering the pump on the with thermostat? Thermostats are 24 volt systems. In order to power on a pump you would need a relay. How are you powering on the fan? I assume using the relay in the oil furnace. If your owb temp drops and your backup heat kicks on how have you isolated your fan to not run 24/7 when the owb thermostat isn't being satisfied?
My HVAC man wired it from a separate thermostat. The HVAC thermostat will be in the off position when the OWB is in operation. Yes I have a relay for the pump and both thermostats are wired to the fan. Just runs when whichever thermostat is online. Is there a high temperature shutdown or anything like that? The thermostat on the boiler is set at 175? Local gauge confirms this temp.
hondaracer2oo4
Feeling the Heat
Sorry I am confused. What pump are you having an issue with? Is it the pump that the thermostat inside your home is suppose to be commanding on? If so you’ll need to follow the power to find out the problem. When the thermostat call for heat it sends power to the pump relay. This energizes the relay making the connection for 120 volts to head to the pump to turn it on.
On another note there is a much better way to hook up your system so that your oil furnace automatically runs as a back up and you only use 1 thermostat for the whole system. The way you have it now means that if the owb runs out of wood you manually have to change over. The automatic way to do this and with only 1 thermostat is that you place a strap on aquastat onto the incoming owb line. You set thst to about 10 degrees below what ever the low set point is on the owb, say 150. Now you use the aquastat to power the oil furnace. So when the owb temp is above 150 the oil furnace won’t have power, when the temp drops below 150 the oil furnace kicks on and takes over automatically.
On another note there is a much better way to hook up your system so that your oil furnace automatically runs as a back up and you only use 1 thermostat for the whole system. The way you have it now means that if the owb runs out of wood you manually have to change over. The automatic way to do this and with only 1 thermostat is that you place a strap on aquastat onto the incoming owb line. You set thst to about 10 degrees below what ever the low set point is on the owb, say 150. Now you use the aquastat to power the oil furnace. So when the owb temp is above 150 the oil furnace won’t have power, when the temp drops below 150 the oil furnace kicks on and takes over automatically.
Seems a little unusual. Your boiler circ pump should be controlled by the boiler. Generally us "second t-stat guys" are controlling a second pump independently.
Has your setup ever worked? Is it possible the relay was wired incorrectly? Are you getting 24V at the relay in order to throw it when the second t-stat calls for heat?
Has your setup ever worked? Is it possible the relay was wired incorrectly? Are you getting 24V at the relay in order to throw it when the second t-stat calls for heat?