Central Heating Programer Problem

cmh_2

Hot water and heating come on as programed.
Hot water reaches temperture and turns off. But this allso switches off the central heating.(At this time the room sat is still calling for heat) If I switch the hot water off in the programer the Heating will come back on.

dieselglider

Can you provide more details? ie, Programmer and valve/s make/model.

samtheman1k

It sounds like resistor R34 on the Flangie board has blown

cmh_2

dieselglider wrote: »

Can you provide more details? ie, Programmer and valve/s make/model.

Honeywell Y plan (Horstmann mid-position 3 way valve,and Horstmann c27 programer) Thanks

Cardew

There are some CH experts on MSE in the DIY section, and Canucklehead(or spouse) a Corgi fitter visit here from time to time.

From my limited knowledge the motorised valve(or circuitry) would appear to be the main suspect; The HW when on is causing the valve to stay in the incorrect position.

If you email Honeywell technical department they might offer some advice - they sent me a set of diagnostic procedures.

dieselglider

cmh wrote: »

Honeywell Y plan (Horstmann mid-position 3 way valve,and Horstmann c27 programer) Thanks

Ok, did a bit of googling, and found the installer plan for your programmer, and also some other info. I think the problem lies with the cylinder stat, when it switches off at the set temp (satisfied), it should give a live feed to the Grey wire on the 3-way valve. This should be also linked to the HW 'off' terminal at the programmer, which yours seems to be from your fault description (which leads me to think that the 3- way valve is working ok).

The easiest check (BEWARE 240 VOLTS!!) is with the HW on, check that the cylinder stat is switching live from one terminal to the other, when turning the temp setting. There should be 3 terminals connected, the 'common' (or 'c') from the programmer HW 'on', and the other two switched, possibly called 'call' and 'sat' (or '1' and '2').

Good luck, and be careful.

cmh_2

dieselglider wrote: »

Ok, did a bit of googling, and found the installer plan for your programmer, and also some other info. I think the problem lies with the cylinder stat, when it switches off at the set temp (satisfied), it should give a live feed to the Grey wire on the 3-way valve. This should be also linked to the HW 'off' terminal at the programmer, which yours seems to be from your fault description (which leads me to think that the 3- way valve is working ok).

The easiest check (BEWARE 240 VOLTS!!) is with the HW on, check that the cylinder stat is switching live from one terminal to the other, when turning the temp setting. There should be 3 terminals connected, the 'common' (or 'c') from the programmer HW 'on', and the other two switched, possibly called 'call' and 'sat' (or '1' and '2').

Good luck, and be careful.

Checked cylinder stat -when calling for heat, 1 and 2 both live. When satified 2 is live. Is this as it should be?

dieselglider

Doesn't sound quite right, but it might depend on the make of stat. It is using all 3 connections?

Has this fault just developed, or always been like this?

Have a look at the Horstmann site, scroll down and download the 'installation' pdf for your programmer. I think wiring diagram no.5 ( you can zoom in) should be what you're looking for. Maybe you could confirm. And here's the Honeywell site 'Y' plan, which seems to using the same standardised wiring.

Btw, I'm no heating expert, just taken an interest today since I've been off work sick..:) Google is our friend!

cmh_2

dieselglider wrote: »

Doesn't sound quite right, but it might depend on the make of stat. It is using all 3 connections?

Has this fault just developed, or always been like this?

Have a look at the Horstmann site, scroll down and download the 'installation' pdf for your programmer. I think wiring diagram no.5 ( you can zoom in) should be what you're looking for. Maybe you could confirm. And here's the Honeywell site 'Y' plan, which seems to using the same standardised wiring.

Btw, I'm no heating expert, just taken an interest today since I've been off work sick..:) Google is our friend!

The systerm has been working well for 5years.
The cylinder stat does use all 3 connections.
Thanks

dieselglider

What are the 3 terminals on the cyl stat called, is it C, 1, 2? Or 1,2,3? I don't think you mentioned the make/model of the stat.

Perhaps an easier test to determine is to check the grey wire connected to the 3-way valve. As I understand it, the grey should be live when either;

A. Programmer HW 'on', cyl stat 'satisfied' (set temp reached);

B. Programmer HW 'off'.

The white wire to the 3-way valve should be live when programmer CH is 'on' and the room stat is 'calling' for heat.

cmh_2

dieselglider wrote: »

What are the 3 terminals on the cyl stat called, is it C, 1, 2? Or 1,2,3? I don't think you mentioned the make/model of the stat.

Perhaps an easier test to determine is to check the grey wire connected to the 3-way valve. As I understand it, the grey should be live when either;

A. Programmer HW 'on', cyl stat 'satisfied' (set temp reached);

B. Programmer HW 'off'.

The white wire to the 3-way valve should be live when programmer CH is 'on' and the room stat is 'calling' for heat.

Hello It's a honeywell stat with C,1 and 2.terminals .
Thanks for your time.
Screwfix do a control pack for £64 guess I could replace one bit at a time.