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cdubber · Sep 9, 2008, 09:22 AM

I have a Myson Fan Convector heater on my central heating circuit.
When it reaches the desired temperature, the fan (operated by the thermostat) keeps coming on and off for just a few seconds. The room temperature is OK, it's just annoying.
Is this a faulty thermostat, or what?

hvac1000 · Sep 9, 2008, 10:13 AM

Yes it could be the thermostat. I would electrically check it before buying a new one.

cdubber · Sep 12, 2008, 03:35 AM

Originally Posted by hvac1000

Yes it could be the thermostat. I would electrically check it before buying a new one.

Thank you for your answer. Thermstat switches on and off, but how can I check upper and lower temperatures as I do not know what these temperatures should be?

hvac1000 · Sep 12, 2008, 03:57 AM

When it reaches the desired temperature, the fan (operated by the thermostat) keeps coming on and off for just a few seconds

You said the fan is operated by the thermostat on this unit. That would be the first place I would test. Next would be any fan relay that might be in the system. One of those components has to be the trouble maker unless the air filter is clogged up causing the problem.

but how can I check upper and lower temperatures as I do not know what these temperatures should be

You will need a manual for that unit in order to know what the high and low temp is supposed to be.
Actually how high and low the temp is has nothing to do with a blower that is acting up as yours first complaint stated.

cdubber · Sep 12, 2008, 11:06 AM

Originally Posted by hvac1000

When it reaches the desired temperature, the fan (operated by the thermostat) keeps coming on and off for just a few seconds

You said the fan is operated by the thermostat on this unit. That would be the first place I would test. Next would be any fan relay that might be in the system. One of those components has to be the trouble maker unless the air filter is clogged up causing the problem.

but how can I check upper and lower temperatures as I do not know what these temperatures should be

You will need a manual for that unit in order to know what the high and low temp is supposed to be.
Actually how high and low the temp is has nothing to do with a blower that is acting up as yours first complaint stated.

Thanks again
Have looked at manual, unit is still under guarantee! There is no relay in circuit. What I really need to know is:
a) Is cycling on and off in seconds normal?
b) If not, can it be caused by anything other than the thermostat?

EPMiller · Sep 12, 2008, 06:40 PM

a)no.

b)yes, but I would like more info. How short is the cycle, 2 seconds? 20 seconds? Where is the thermostat? Would you know if the thermostat is mechanical or electronic? Is the unit "self contained" or is it constructed of several separate units? Did a professional install it or did you DIY?

Really, if it is under warranty, go that route.

EPM

hvac1000 · Sep 13, 2008, 04:27 AM

I agree the warranty should cover that.

cdubber · Sep 13, 2008, 07:01 AM

Originally Posted by EPMiller

a)no.

b)yes, but I would like more info. How short is the cycle, 2 seconds? 20 seconds? Where is the thermostat? Would you know if the thermostat is mechanical or electronic? Is the unit "self contained" or is it constructed of several separate units? Did a professional install it or did you DIY?

Really, if it is under warranty, go that route.

EPM

Thanks for your comments.
Cycle is approx. 3 seconds on and 10 seconds off, when it reaches the set temperature.
Themostat is electronic and housed within the self-contained unit, together with a water filled radiator and fan. Unit was professionally installed.

EPMiller · Sep 13, 2008, 07:10 AM

Sounds like a bad design. Likely the tstat is too close to the heat source. Get warranty service. Those issues are a pain. You might have a couple go-arounds. :(