heating problem

Reddevilman

Hi all im looking some advice with my oil heating,the problem im having is the upstairs heating wont fire up the boiler on its own.I have a three way horstmann h37xl controller to heat hot water heating downstairs and heating up stairs all seperately with their own motorised valves,the only way I can get heat upstairs is to turn downstairs on and when I turn downstairs off the boiler stops even though upstairs is swithed on at the controller And the thermostat and motorised valve lights are on.

Robbie.G

It sounds like the programmers wiring is mixed up.
Do the zones correspond to the programmer.
Possible programmers fecked or problem with system wiring

scudo2

Did it work the three zones ok previously ?
If yes then your problem is upstairs motorized valve is not opening enough to switch the internal micro switch to send power to the boiler.
It needs replacing, call service eng. as a person on the job might easily spot that it's something else, before you spend a fortune on non returnable parts.

shane0007

Here's my two pence worth. Previously it was a standard programmer which was wired to switch on the boiler. Beside it was two switches, one for upstairs & the other for downstairs. These were wired to motorised valves but not interlocked with the boiler. Just an electric summer valve.
A three channel timeclock was added to do away with the switches, but still not interlocked with the boiler, hence it will only bring on the boiler if hot water is on also.

Reddevilman

The programmer did work ok before I bought the house as I bought it from a friend, ive just moved in, if the motorised valve is faulty hows it possible to turn upstairs on along with downstairs but not upstairs on its own.shane the 3way programmer was put in when the house was built about 5 years ago, I tried a different method of turning downstairs heating on then Turning upstairs on then downstairs off and leaving upstairs on the boiler stays on about 5mins then cuts out.

scudo2

Reddevilman wrote: »

The programmer did work ok before I bought the house as I bought it from a friend, ive just moved in, if the motorised valve is faulty hows it possible to turn upstairs on along with downstairs but not upstairs on its own.shane the 3way programmer was put in when the house was built about 5 years ago, I tried a different method of turning downstairs heating on then Turning upstairs on then downstairs off and leaving upstairs on the boiler stays on about 5mins then cuts out.

Clock only turns on the motorized valves ( not the boiler )

When the valve opens fully it then ( the valve ) sends power to the boiler.

Upstairs valve is opening but faulty, so it not sending power to the boiler, boiler is only getting power when one of the other good valves are also switched on.

Understand now ?

shane0007

It really depends on how the system is wired. If wired correctly, the MV brings on the boiler as Scudo says via it's internal micro-switch. Most electricians do not wire them in this correct way, but just wired the programmer live to open the valve & switch on the boiler. The micro-switch is doing nothing in this instance.

So it could just be a faulty programmer, which the H37XL is prone to going faulty after power surges during power cuts.