Heating not working. Help required to Diagnose

[LKO]

I have a Glowworm Ultimate 80FF boiler providing hot water and central heating (more than 15 years believe). Cold water tank in attic. hot cylinder (CYL) in airing cupboard with 3 port divertor valve (VALVE), drayton control programmer (PRG) and grundfos alpha pump(PUMP) fitted as well. Recently heating doesnt come on even when initiated by PRG and room stat (ROOMSTAT). It did come on if HW is selected on PRG. Now even that alternative is not working properly with requirement to increase cylinder thermostat (CYLSTAT) manually, which is troubling because unless hot water is utilised, heating will not come up again.

Additional notes
1. It seemed indicator on VALVE wasnt moving till few days back. It started moving after I switched off the power to control box in airing cupboard. It makes a clicking sound oscilating 2 degrees when both CH and HW are selected after power up. It gets stuck on right (CH) selection if CH is selected only on PRG even once and doesnt go back to HW setting, or middle oscilating setting unless power is switched off to PRG.
2. PUMP only comes on when CYLSTAT is increased and shuts off when it appears CYLSTAT is satisfied by boiler.
3. Opened ROOMSTAT (honeywell 6830 believe) and seems to give correct signalling on selection.
4. Heating (radiators dont heat up) doesnt come on even when both HW and CH are ON in PRG
and ROOMSTAT turned to 30 (and ROOMSTAT giving audible click at 15)

my initial belief was that either the divertor valve VALVE (drayton bgmvsp-23) motor or the actual 3 way valve under it is faulty. Both of these will require draining which seems too much to take on. But the recent development with PUMP makes me wonder if its something to do with electrics.

Need help to diagnose the issue and faulty part in the system.. Urgent help appreciated as kid under 2 years old

 

[muggles]

Urgent help appreciated as kid under 2 years old

I'm not sure this really makes a difference...

Sounds to me like your 3-port valve isn't working correctly. A bit of electrical testing with a multimeter would absolutely confirm, but the symptoms you describe ate consistent with that fault

 

[45yearsagasman]

The very first thing I would check is for power to the synchron motor inside the 3port valve actuator. In my experience a failed motor is the most likely culprit. You will need a multimeter and a degree of skill to go any further.

 

[LKO]

I got a multimeter. What should be I be looking for ? Just voltage/live coming on.
I have been trying to open the 3 port valve box on top but not sure how to open the blue covering ... could you explain
photo attached... the valve gets stuck on the right as it shows

DSC_0032

• LKO
• 29 Feb 2016

 

[Echo the husky]

It's easiest to test at the terminals in the junction box where the black flex goes to. As this is a British Gas valve I would expect a poorly made join to be present in the valves flex, if so a loose connection is possible here too. With meter set to measure AC volts, one test probe connected to neutral for all measurements. If the motor never moves, that is a likely suspect. If it moves but does incorrect things either the micro switches in the valve are faulty, an external control is faulty, or there is a wiring error/loose connection etc. This is what should happen:

Heating on at programmer, room stat turned up, hot water off at programmer:
Grey wire 240V
White wire 240V
Orange wire 240V
Valve right over to heating only

Heating on at programmer, room stat turned up, hot water on at programmer, cylinder stat calling:
Grey wire 50-150V
White wire 240V
Orange wire 240V
Valve at mid position

Heating on at programmer, room stat turned up, hot water on at programmer, cylinder stat satisfied:
Grey wire 240V
White wire 240V
Orange wire 240V
Valve right over to heating only

Heating off at programmer, hot water on at programmer, cylinder stat calling:
Grey wire 0V
White wire 50-150V
Orange wire 240V
Valve spring returned to hot water only

Depending on what gets switched off last the valve may spring return to HW only or be held fully open to CH only when everything is off.

 

[LKO]

Thanks Husky for the detail.

Following are the voltages in the junction box in RED. Does this mean there is a short somewhere or error/losse connection I couldnt verify. The wires going in the junction box appear good and firm. Tried to open the white connector going to actuator but nut is stuck couldnt verify. Also still not sure how to remove the blue cover from the actuator top if that is the next step to check electrics. Assuming I can open it, is it possible to change the synchron motor while the actuator is still connected to the actual valve or do i need to take it out. Also does this step require draining down the system. Please advise

It's easiest to test at the terminals in the junction box where the black flex goes to. As this is a British Gas valve I would expect a poorly made join to be present in the valves flex, if so a loose connection is possible here too. With meter set to measure AC volts, one test probe connected to neutral for all measurements. If the motor never moves, that is a likely suspect. If it moves but does incorrect things either the micro switches in the valve are faulty, an external control is faulty, or there is a wiring error/loose connection etc. This is what should happen:

Heating off at programmer, Hot water off at programmer
Grey wire 245V
White wire 0V
Orange wire 0V
Valve at left side (valve goes to right initially after power has been cut off to junction box)

Heating on at programmer, room stat turned up, hot water off at programmer:
Grey wire 240V 243V
White wire 240V 245V
Orange wire 240V 22-26V
Valve right over to heating only Valve to right only

Heating on at programmer, room stat turned up, hot water on at programmer, cylinder stat calling:
Grey wire 50-150V 0-80V
White wire 240V 240-1000V
Orange wire 240V 243V
Valve at mid position Valve at mid position (oscillating a little with clicking sound)

Heating on at programmer, room stat turned up, hot water on at programmer, cylinder stat satisfied:
Grey wire 240V 243V
White wire 240V 243V
Orange wire 240V 22-26V
Valve right over to heating only Valve to right only

Heating off at programmer, hot water on at programmer, cylinder stat calling:
Grey wire 0V 0V
White wire 50-150V 7V
Orange wire 240V 245V
Valve spring returned to hot water only Valve back to left position (I had switched off power in b/w before testing this)

Depending on what gets switched off last the valve may spring return to HW only or be held fully open to CH only when everything is off.

 

[muggles]

You're registering 1000v on the white with both heating and hot water calling!? Sounds like your multimeter is goosed, time to buy a new one!

 

[Echo the husky]

Providing the orange wire is properly connected in the terminal of the junction box, you need a new valve actuator. The microswitch isn't putting power onto the orange wire to fire the boiler and pump. The replacement will be grey/white rather than blue, BG have the blue ones made especially.

That stupid connector is something to do with British Gas and I wish they would stop fitting them, these connectors are not designed to be used this way.

Before you replace the actuator, if the valve flex is long enough to reach the junction box, I would cut off the connector and discard it and wire the valve flex directly into the junction box. If it works now there must be a poor connection in the connector, which isn't surprising seeing as the single insulation is visible outside the connector.

If not, it's new actuator time. There is a little plastic release button near the bottom of the actuator, press it in and the actuator should pull off. The button is visible on the right in your photo.

 

[Echo the husky]

You're registering 1000v on the white with both heating and hot water calling!? Sounds like your multimeter is goosed, time to buy a new one!

That is an odd reading! You sometimes get weird readings when the power is back fed through the diode/resistors, not sure why on that particular one though!

 

[Agile]

He may mean 240v on the 1000v range!

 

[LKO]

You're registering 1000v on the white with both heating and hot water calling!? Sounds like your multimeter is goosed, time to buy a new one!

That is an odd reading! You sometimes get weird readings when the power is back fed through the diode/resistors, not sure why on that particular one though!

I observed voltage fluctuating between the 240 and 1000V (multimeter range was set as 750 first so I reset to higher but still got the same fluctation). Given all the other readings of 240 were constant, I thought this was due to faulty connection/wiring only rather than a fault with multimeter. The multimeter is not a costly or professional one, and has been used sparingly over the last few years. Never had reason to doubt it before.

Thanks all for the quick followup and advise. I will try the flex reaching to junction box first before trying to open the actuator...

Does the diagnosis mean replacing synchron motor is no longer an option ? I was looking at 3 port actuator and with actual valve its costly at £115, while synchron motor appeared to be £16. Also I read that Honeywell 4073 could be a replacement and more reliable (preferred by pros). Will it be similar to fit or should as a beginner I go with Drayton type only if I have to replace actuator and not the synchron motor....

 

[Echo the husky]

The motor is fine as heating works when hot water is also on. You need this part. (actuator without valve body) May be available cheaper elsewhere, City Plumbing sell Drayton valves re-branded Iflow which may be a cheaper than buying Drayton. You can change to Honeywell but that requires replacing the valve body as well so the heating system will need draining down.

 

[Agile]

I find the Drayton type to be less reliable and also virtually impossible to replace just the motor.

If time on the job is not important then replace with a Honeywell or the Tower or Corgi branded copies.

I see little difference between the original and the copies.

Tony

 

[Echo the husky]

Do check it isn't a bad connection in the white connector first though!

 

[LKO]

Havent been able to check the electrics ...going to do that today...

Meanwhile was searching the shops for the replacement but confused as there are so many out there.... not sure whats the difference after I narrow down to 3 port and 22mm (measured the pipe diameter)...

Couldnt check City Plumbing as the prices and stock availability as Husky advised because they want account to be opened and only open it for trade customers which I am not. Also if honeywell requires draining then it means additional costs because the plumber I had called said we need to call CORGI folks if you want draining down.

Following is the results of search for part so far then
Honeywell are not coming below £95 (actuator only) from proper shops with cheapest one was ebay

links
http://www.ebay.co.uk/itm/Honeywell-V4073A1039-3-Port-Mid-Position-Diverter-Valve-22mm-/272123421762

Got 3 matching from plumbcentre
http://www.plumbcenter.co.uk/webapp...toreId=10201&ddkey=http:AjaxCatalogSearchView

Got 2 matching from Screwfix
http://www.screwfix.com/search?sear..._-+Honeywell&gclid=CMWq1LfnpMsCFcYcGwodl2MPbA

Incidently the drayton one has dropped in price from £76 to £56.. tempted with it...
http://www.wickes.co.uk/Drayton-MA1-679-3-3-Port-Valve-Mid-Position-22mm/p/228406

This has a valve as well - assume I will be able to dismantle and use the actuator only
or if not possible the one below for £64

http://www.screwfix.com/p/drayton-mid-position-valve-actuator/40818? source=aw&awc=1228_1456865867_25c86adb7508b306b9fae7e9f91aecf5&cm_mmc=AffiliateWindow-_-Editorial+Content-_-DeepLink-_-58258

Please advise.... thx in advance