Myson Apollo 40B & Honeywell froststat operation

[Johnboy]

Hi,

Question about the operation of Frost stat on a Myson Apollo 40B boiler.

For a couple years I have had the Hi stat on the boiler fail corresponding to the time when the frost stat has come on due to very cold weather. The Hi stat has been replaced and all seemed well.

This year (and maybe last year - I’ve slept since then) when the Honeywell frost stat kicks in the heating in the radiators start heating up and do not turn off when the room thermostat setting is reached e.g. the room thermostat is set at 16DegC and the actual room temperature gets up to over 20DegC. Putting the thermostat switch on the boiler to low helps a bit but I have had to put it on the O setting at times.

The heating guy I have used has said that on older boilers that Frost-stat *does* make the actual heating of the system kick in. I have read that Frost-stats should just move the water around the systems to stop the water freezing.

Any advice on which is correct:

a) The frost-stats on Apollo 40B will kick in the heating and I’ll just have to out up with it
b) The frost stat should just move the water round and there is an issue with it/issue with wiring?

I have also read that the frost-stat simply moves the water around the system where-ever the 3-way valve was last positioned in and for winter that's normally through the radiators not just the hot water-tank.

Many thanks.

 

[PETE 123]

Its wired to over ride all controls, if the roomstat was wired in under this condition then the boiler would not fire when heat was called for by the frost stat if room stat was on low setting for some reason

 

[Johnboy]

Thanks for the reply, Pete.

So basically, the Froststat has to kick the boiler in and the radiators will still get hot rather than just moving the water around.

Looks like I'll have to put up with a hot house...

 

[lame plumber]

you should also have a pipe stat fitted so that when the flow back to your boiler reaches a nice warm temp 30/40 then it turns off the boiler again, once the pipes cool and its still cold he frost stat can kick in again. Stops you heating up your house all night and wasting money, only costs around 20-30 quid to buy one and a sparky or plumber to fix some say plumbers musnt touch elecs anymore!

 

[Johnboy]

Many Thanks I'll look into a pipestat - hate wasting money on wasted heat.