Programmer advice

[panzerattack]

Hi,

I have just moved into a house with an old Gloworm Fulesaver MK2 boiler and HW cylinder installed. I want to get this replaced with a new boiler (probably a combi).

Current setup:
3x 2 port valves (HW, CH1, CH2)
2x programmable room thermostats (Honeywell CM907)
1x 2 channel programmer (Honeywell ST9400C)

If I get a combi boiler installed am I correct in thinking that the HW 2 port valve will no longer be needed and the current programmer will need replacing for a single channel version or can the existing one still be used?

Thanks for your help.

 

[simond]

You could keep the programmer, replace it with a single channel unit, or remove it altogether and use the CM907s.

I would do the latter with a combi.

 

[D_Hailsham]

Before you decide on a combi, you need to check three things:

1. Cold water mains flow rate
2. Cold water mains pressure
3. Maximum instantaneous hot water requrements.

The last will depend on how many baths and showers there are and how many could be running at the same time.

If you go for a combi you will not require the HW 2-port valve.

If the ST9400C is set to constant for the heating and timed for the hot water, it can be removed if you have a combi. But the wiring for the CM907s will have to be modified, which is an easy job.

 

[panzerattack]

thanks for the advice guys.

 

[gas4you]

If you intend to keep the ch as 2 zones you will need a 2 channel programmer to control the 2 zone valves. The combi will obviously take care of the HW.

It will have to be wired as a simple S plan to the combi.

Or have I missed somethiong in your post

 

[D_Hailsham]

have I missed something in your post

Yes

2x programmable room thermostats (Honeywell CM907)

 

[gas4you]

ok