Lots of hot water but no central heating

[Starmatt]

evening,

been having a bit of an issue with my CH the last couple of days. i have plenty of hot water but no CH.

i have a glow worm Micron 50ff, about 7 years old, no problems before now. was checked by engineer about 6 months ago.

when CH turned directly on boiler does not fire at all. nor does it come on for timed heating. if hot water is run for a while it fires and reheats tank.

if i move the motorised valve (honeywell 2 way i think) to manual rather than auto the boiler starts to fire but then shuts off and the reset light flashes.

any ideas as i am out! let me know if anyone needs more details.

SM

 

[Hugh Jaleak]

Possible motorised valve problem. Assuming you have 2x 2 port valves (1 for HW, 1 for CH), the CH valve is duff and not working. Opening it manually may energise the boiler and pump indicating the electrical side is operating ok, but not actually opening the valve itself to allow a path for the water to flow.

Result, water cannot circulate, boiler overheats and cuts out. Try removing the head of the valve (if removable type) and operating spindle with pliers. Then switch HW on, if valve is opening then hot water from the boiler should get past the valve into the CH. (Boiler and pump being energised by HW side, and alternative path for flow available through HW circuit so boiler wont overheat.)

 

[Armo74]

Are you sure it's a 2 port valve? Sounds like the motor has failed.

 

[Starmatt]

model of valve seems to be v4073A1039 if that's any use.

Untitled

• Starmatt
• 8 May 2012
• 1

google does seem to agree its a 3 way. my mistake.

just turn heating on direct again an boiler now fires for about 5 mins then turns itself off again!

 

[Agile]

You need to feel/measure the flow and return temps at the boiler.

Sounds as if there may be a lack of flow.

Setting the valve to the manual locked position may get you CH while the water is being heated.

Turning the cyl stat to 80 C and boiler flow to 65 C will keep both on as long as you like as the cyl will never reach the selected temp.

Thats only a temp work around until you have fixed/replaced the valve.

Tony

 

[Starmatt]

deffo seems to be the motorised switch that is the issue. i took the cover off and have discovered that when in manual the burner fires and then the gearing seems to slip back just a notch or two which then disconnects the contacts and turns it off. i can hold it in place with a screwdriver an it works fine.

obviously this is not a permanent solution!

i think i would be correct in saying its time to get the pro's in.

 

[Starmatt]

so if its the motor thats gone, how easy is it to replace?

 

[Wildeman]

evening,

been having a bit of an issue with my CH the last couple of days. i have plenty of hot water but no CH.

i have a glow worm Micron 50ff, about 7 years old, no problems before now. was checked by engineer about 6 months ago.

when CH turned directly on boiler does not fire at all. nor does it come on for timed heating. if hot water is run for a while it fires and reheats tank.

if i move the motorised valve (honeywell 2 way i think) to manual rather than auto the boiler starts to fire but then shuts off and the reset light flashes.

any ideas as i am out! let me know if anyone needs more details.

SM

I have this very same issue with my system which has a Glow Worm Ultimate boiler connected to a Wilo Gold Pump and Sunvic 3 Port mid-position valve.

I have replaced the actuator and valve body this week and fully drained, run Sentinal X800 through the sysyetm and also flushed fully again from all the downstairs drain off points as well as the drain on the return to the boiler.

The HW on it's own is fine, the H/W and central heating is fine but when the stat on the cylinder as reached the desired temp and the valve moves to C/H only the boiler fires for about 3 minutes and then goes out and the water flowing through the valve and radiator pipe work is bearly warm!!!

I have tried the work around to turn the cylinder stat up to max and turn the boiler down to keep the valve in the mid position but the tap in the kitchen cannot have water hotter than 65 degrees going through it.

Any ideas?

 

[Agile]

Better to solve the problem that to do work arounds.

They are only for me to keep the customer warm overnight until I can return with the new part!

NOT as a permanent solution to avoid buying a new part!

Tony

 

[Wildeman]

Better to solve the problem that to do work arounds.

They are only for me to keep the customer warm overnight until I can return with the new part!

NOT as a permanent solution to avoid buying a new part!

Tony

I fully agree Tony but I have replaced the valve and actuator, pump all the rad's except 2 have new TRV's on them and the system has been cleansed and fully flushed so now not sure what else to try or replace - any ideas?

 

[Agile]

You seem to have a wiring fault!

Would have been better finding that than replacing parts!

Photo of wiring to timeclock?

Tony

 

[Wildeman]

You seem to have a wiring fault!

Would have been better finding that than replacing parts!

Photo of wiring to timeclock?

Tony

I did think that too Tony but have had two seperate sparks look at it and they say it is wired correct for a Y-Plan system

The system used to have a danofss 102e5 programmer which one of the electricians replaced with a Sunvic 207XLS 2 channel programmer to allow hot water and central heating independantly.

I have a Sunvic 3 port mid position valve (DSV2291) and Sunvic TLX6501 Programmable room stat and Wilo Gold Pump

When just the heating is selected on the programmer or both C/H and H/W are on the programmer but the cylinder stat is satisfied I have checked and the valve moves to the correct position, the pump runs and the boiler fires (but then goes out after about 1-2 mins) - the wiring diagram I made is in my albums

Can you take a look at it and see if you can see the issue and I will check again over the weekend the wiring if you can give me some pointers as I am competent with a test meter.

 

[Agile]

What do you expect me to look at?

EDIT You have put a sketch on your profile. I cannot follow it very well. Can you increase the contrast?

What is that? Did YOU draw it from the existing wiring? Or was it used to do the installation???

A photo of the back plate would be helpful!

Why do you think electricians would recognise faults? Most only do power wiring!

A heating engineer would be my choice but even so only about 15% are very competent with wiring.

About 35% don't even do the wiring themselves!

Tony

 

[Hugh Jaleak]

Are you certain valve is ok? Sunvic valves aren't the most reliable on the market, some reading here: http://www.seered.co.uk/sunvic.htm

Excellent Y plan diagrams here: http://octaveblue.co.uk/central_heating.html

 

[Wildeman]

What do you expect me to look at?

EDIT You have put a sketch on your profile. I cannot follow it very well. Can you increase the contrast?

What is that? Did YOU draw it from the existing wiring? Or was it used to do the installation???

A photo of the back plate would be helpful!

Why do you think electricians would recognise faults? Most only do power wiring!

A heating engineer would be my choice but even so only about 15% are very competent with wiring.

About 35% don't even do the wiring themselves!

Tony

Tony,

I have uploaded a sketch of my exact wiring (after carefully tracing every wire) to my albums and have the contrast on max so you should be able to view it and there are photos of the wiring to the programmer too. (http://www.diynot.com/network/Wildeman/albums/)

Looking at Y-Plan wiring digrams on the internet it would appear to be wired correctly.

One thing I did try over the weekend was to fire the system up called for heat to both H/W and C/H and as expected the pipes to the cylinder and radiators were red hot within minutes. I then removed the actuator to the valve and manually moved the valve from the mid position to the C/H only position, the tone of the pump changed and after a rushing sound of water within minutes the pipe to the pump and from the valve were very cool and within 5 minutes all the raditors were cool. I noticed than when I moved the valve after a few minutes the boiler went out.

I then moved the valve back to the mid position and the boiler lit and within minutes everything was red hot again after a rushing sound of water through the pump and pipes. Does this rule out a wiring issue?

Could this be an airlock?

Thanks

Andy