central heating timer

[foghorn]

problem with central heating timer ie
does not allow hot water and heating on at the same time they just cancel each other out
any ideas much appreciated

 

[stef]

If it is a combi boiler then you can't have both at the same time.

 

[stef]

I believe that domestic hot water takes priority over central heating as well.

 

[foghorn]

i have a combi at home cental heating and hot water works fine togeather can select either just hot water or heating and hot water

 

[stef]

Yeah, you are right, just checked with mine, both working together. It is a fairly new Vaillant boiler. The old one was an Alpha boiler, it couldn't do both at the same time.

 

[foghorn]

when having hot water and heating on at the same time they just cancell each
other out not a combi system

 

[stef]

So you mean on the timer itself then? That would depend on the timer brand and it's programming options. Why is hot water on a timer in the first place? You want hot water instantly and not just at certain times.

 

[ayjay]

is it a timer with a switch on the back?
some had a switch that would affect the h/w-c/h selection

 

[rsp84]

On a combi, when there is demand for hot water, ie turning on a hot tap, the boiler will stop heating through the central heating exchanger but the pump will still run otherwise the boiler will overheat and lock off.
Like said above, must be a programmer issue.

 

[foghorn]

o thanks for the help will try and replace timer see if this cures the problem
many thanks
foghorn

 

[D80]

Hortsmann programmer by any chance?

Is this a new install or has the fault recently developed?

 

[UNG]

when having hot water and heating on at the same time they just cancell each
other out not a combi system

So what have you checked or should we try our crystal balls and see if they can identify the fault

 

[SYKRAPS]

Sounds to me (if the system is a y-plan or s-plan) that there is a wiring connection fault or one of the valves has developed an issue, I think that you should see if the valve/valves are opening and closing on demand from the clock and stats.

Are both of the lights illuminating on the clock correctly when activated?

If it is a combi the clock is only for the heating so I am assuming that it is a plan of some kind.

 

[gavinmc]

What make is your timer