No HW on ancient system

[meatpie48]

I've been having problems with my my HW. CH heating is working fine but we are not getting any hot water. I've changed the actuator on the 2PMV & it makes the correct noise but the boiler doesn't seem to fire up for water heating. For the past 2 weeks I have had the actuator removed off the HW valve & I've manually opened it. We have had HW running into the cylinder when the heating has been switched on. It has been fine, albeit bloody hot but with the new actuator the problem is still there.

The boiler is a terribly ancient but very reliable Ideal Concord WRS series.

Are there any things that I could check/replace to get the boiler firing on HW operation again?

Many thanks

 

[Hugh Jaleak]

It sounds like an electrical issue IMO. The boiler is not getting the call to fire when the HW stat is calling for heat. Has it always done this or has it become a recent problem?

 

[Ronald0]

Just to expand on Hugh's excellent advice. Turn down room stat to zero and turn up cyclinder stat high. Does boiler fire?

Is there a demand light on the front panel?

If not you need to check for the presence of a switched live.

 

[meatpie48]

Apologies for the late response!

I've had the problem for about a month. I've had to wait 2 weeks for the delivery of the new actuator & whilst this happened I manually left the valve open so I could get HW off the CH system.

Now I have changed the actuator following all the instruction provided I have had no joy.

Regarding the Stat options, There is one CH stat downstairs, do I turn this right down to 0/off & regarding the HW stat, do I turn the one on the cylinder right up, or the dial within the boiler housing right up?

Yesterday I turned the Cylinder stat up to 70 from about 55 & it sounded like it was doing something but the burners did nothing on the boiler.

Regarding a light on the front panel, I've got nothing actually on the boiler but a separate control, CH/HW/Timer. The light does come on when switched to "On" but again the boiler doesn't fire.

How do I find whether there is a switched live? All electrics have been untouched & I made sure that all connections from the terminal block feeding the MV's were "true & secure".

All advice would be very welcomed as my Mrs is giving me a ton of earache!

 

[Hugh Jaleak]

This is probably one for MANDATE or D. Hailsham who are the resident experts on motorised valves! From my understanding, the stat should supply power to the valve to open it when it calls for heat. When the valve opens fully, it activates a microswitch, that in turn then energises the boiler etc to fire. From your description I suspect the valve may be motoring across, but the microswitch isnt allowing power to the boiler for some reason.

Stats, roomstat on wall-down, boiler-leave alone, cylinder stat-up. What happens? If the boiler doesnt fire then there are some electrical checks you can carry out if competant and have a multimeter.

 

[Ronald0]

[Stats, roomstat on wall-down, boiler-leave alone, cylinder stat-up. What happens? If the boiler doesnt fire then there are some electrical checks you can carry out if competant and have a multimeter.[/quote]

Yes, leave boiler control stat on high.

You have an S Plan system, with two, 2 way MVs.

If you are competent with mains electricity, check that you are getting 230V on the orange wire from the HWMV at the terminal box when there is demand for HW.

If so, armed with your boiler manual, check for presence of 230V at the switched live terminal on the boiler. If you are not getting a switched live at the boiler, check continuity back to HWMV via terminal box.

If demand for heating only, fires the boiler, boiler must be OK.

 

[twgas]

turn HW off and look at the underside of the actuator to see the position of the drive slot, then, with the actuator still off the valve, turn the HW on and see if the drive moves. Report back your findings.

 

[meatpie48]

many thanks for your help. Turning the stat up method worked a treat.

 

[Hugh Jaleak]

Cylinder stat should be set at about 60c, any lower and possibility of Legionella bacteria developing, any higher and it can cause scaling up in hard water areas. If you need stat higher for it to work then there is another problem IMO.