Hi,
I have a boiler unit in my house that heats a 3 zone baseboard heating system.
One of the zones is only getting intermittent heat and I'm having trouble
sorting out whether the culprit is the thermostat, relay or circ pump.
I checked the other zones' thermostats and it seems that the "command" for heat on is
to short the leads, so I disconnected one lead from the thermostat and shorted
the low voltage leads on the relay box. This yielded the satisfying clunk of
the solenoid engaging, the slight hum of the suspect zone's circ pump and the
zone's feed pipe getting hot.
So, I thought "done" - the culprit was the thermostat.
However, I left the leads shorted for about 1 hour while I cleaned up all the
periphery and tended to other things. I came back to find the feed pipe to
that zone again cold. The boiler was running and the solenoid still responded
to short the low voltage leads, but it was clear (at least to me) that the
circ pump wasn't moving water.
So, I see these possibilities to explain the intermittent behavior.
1) the solenoid is physically engaging but the relay isn't reliably
providing power to the circ pump,
or
2) the circ pump is near dead and intermittent.
This is an old system, and I don't know what type of voltage is going through
the relays to the circ pumps.
Any hints on how to sort this out ?
Thanks,
hh
I have a boiler unit in my house that heats a 3 zone baseboard heating system.
One of the zones is only getting intermittent heat and I'm having trouble
sorting out whether the culprit is the thermostat, relay or circ pump.
I checked the other zones' thermostats and it seems that the "command" for heat on is
to short the leads, so I disconnected one lead from the thermostat and shorted
the low voltage leads on the relay box. This yielded the satisfying clunk of
the solenoid engaging, the slight hum of the suspect zone's circ pump and the
zone's feed pipe getting hot.
So, I thought "done" - the culprit was the thermostat.
However, I left the leads shorted for about 1 hour while I cleaned up all the
periphery and tended to other things. I came back to find the feed pipe to
that zone again cold. The boiler was running and the solenoid still responded
to short the low voltage leads, but it was clear (at least to me) that the
circ pump wasn't moving water.
So, I see these possibilities to explain the intermittent behavior.
1) the solenoid is physically engaging but the relay isn't reliably
providing power to the circ pump,
or
2) the circ pump is near dead and intermittent.
This is an old system, and I don't know what type of voltage is going through
the relays to the circ pumps.
Any hints on how to sort this out ?
Thanks,
hh