zoning my combi now has intermittent fault

[mf1290]

I have a WB 550 cdi highflow installed about 2 years old at the time of a large home extension. 3 weeks ago I had a gas engineer install 2 two port zone valves to separate the new from the old areas of heating. A straight forward install of the valve on the flow to the existing heating circuit and a valve on the flow of the new area. The WB dt20rf thermostat and twin channel prog were removed and replaced with an external drayton twin channel prog and two Siemens wireless thermostats.

All seemed ok but within 24 hrs the hot water would not fire up on demand from a tap, to rectify the fault I would need to turn on the heat and then call for water. The fault seemed to be getting worse with no shower in the morning (without going and turning on the heating first etc). From this set up the hot water is now not programmable to heat the internal store of water.

Called the engineer out who has temporarily replaced the programmer and thermostat and the fault has disappeared, he is due to come back and recify whatever but I wanted to get a heads up on what may be wrong.....

Should there be a bypass installed?, I have trv's on all rads except on a bathroom radiator in each of the two zones......

Is the fact that the boiler is now running as a pure combi without the water store creating a fault ?, should there be another programmer for the water?

I first assumed that I had a faulty flow switch or diverter valve but the fault is cured with the reversion to the original set up (and the zone valves locked open)....

Any ideas anyone please??

 

[Mike Jackson]

Sounds like a wiring issue to me. There may be a plug or link that is removed when the Worcester prog is fitted.

 

[mountainman]

Sorry mf1290 but i don't believe that you should be trying to out think your installer before he has the opportunity to remedy the problem.
MM

 

[mf1290]

Sorry mf1290 but i don't believe that you should be trying to out think your installer before he has the opportunity to remedy the problem.
MM

ok point taken, however he has returned and didn't know what was wrong so he replaced the original programmer. He's due back but isn't able to indicated what he's going to fix or why. Not a question of trying to 'out think' anyone, this isn't a game of chess... If my car is broken I try to understand what is wrong before taking it to a garage, and to be quite honest I thought this forum is for for asking questions about boiler problems from people in the trade who may be able reply with the benefit of professional experience rather than tell the poster to leave it to the professionals. Anyway mountainman, thanks for your input but I take it that you don't know what's wrong - like the guy who installed the zone valves..

 

[mf1290]

Sounds like a wiring issue to me. There may be a plug or link that is removed when the Worcester prog is fitted.

Thanks MJ, guess the engineer will review his wiring........

 

[Howsie]

It's a case of working through the fault. If it worked originally and has stopped it could be a number of things.

I'm always happy to talk my customers through the problem and fix but I won't speculate until I know for sure what's wrong. It doesn't mean I don't know what I'm doing, it means I'm not guessing. Sounds to me like this is where your chap is at.

 

[hammers4spanner]

Haha had to chuckle at the reply then , i am no sparky but when i read this post it kinda does point towards a electrical issue simply because it does work on old prog thermostat and not on new . Thats would be my train of thought on it ,regarding mountainman comment it is annoying when you arrive at a job and someone is over your shoulder trying to out think you i would charge a higher amount if i had a cust like that if i'm honest,,,kinda annoyance money.

 

[mf1290]

Haha had to chuckle at the reply then , i am no sparky but when i read this post it kinda does point towards a electrical issue simply because it does work on old prog thermostat and not on new . Thats would be my train of thought on it ,regarding mountainman comment it is annoying when you arrive at a job and someone is over your shoulder trying to out think you i would charge a higher amount if i had a cust like that if i'm honest,,,kinda annoyance money.

thanks for the reply, still don't get the 'out thinking' thing......... I'll be at work when he's fixing the problem so there goes the over the shoulder annoyance factor which leaves me thinking that gas men don't like customers to know too much about stuff...hmmm maybe a conspiracy theory there ;-)

My man is returning with another man to fix the problem, hopefully wiring, maybe I should ask for a rebate...kinda annoyance money!

 

[dancinplumba]

you will need 3 channel programmer.
imo
and stick with same manu for all components.
imo

 

[hammers4spanner]

haha not a conspiracy theory its called paying insurance/gas safe theory!!

 

[Millsy 82]

The hot water wont work without the store being heated as thats the water that heats your hot water it has to have a hot water programmer. I havnt had to wire an external programmer into a highflow so cant really help that much.

 

[Nostrum]

Sounds like maybe back feed onto the PCB, did he wire the 2 zone valves through a wiring centre type junction box or was it all wired direct back to the boiler?

 

[Nostrum]

Actually having re -read the post and replies, sounds like the old programmer was taken out but the link for hot water wasn't replaced. if that's the case then you need to make sure that you still have timed control for your hot water rather than relying on the thermostat otherwise you'll be wasting heat as the heat store bounces off thermostat short cycling 24hrs and it won't comply to part L regulations either.

As dancin said, you need 3 channel's, but you could wire the zones like an S plan with a wiring centre using the switched live (room thermostat) terminal I think. Leave the existing programmer in situ with the heating set to constant, the hot water side would work as it did.

Off the top of my head I think that would work!? :smart:

 

[dancinplumba]

Actually having re -read the post and replies, sounds like the old programmer was taken out but the link for hot water wasn't replaced. if that's the case then you need to make sure that you still have timed control for your hot water rather than relying on the thermostat otherwise you'll be wasting heat as the heat store bounces off thermostat short cycling 24hrs and it won't comply to part L regulations either.

As dancin said, you need 3 channel's, but you could wire the zones like an S plan with a wiring center using the switched live (room thermostat) terminal I think. Leave the existing programmer in situ with the heating set to constant, the hot water side would work as it did.

Off the top of my head I think that would work!? :smart:

agree 100%

 

[Nostrum]

agree 100%

Yiippppeeeeeeee!

:wink_smile:

 

[mf1290]

Yiippppeeeeeeee!

:wink_smile:

thanks for all the replies, as i understand it - it has been wired like s plan through a wiring centre, guess it will need an additional programmer for the water... I'll reply when the engineer has been back...... thanks again for all the replies

 

[tamz]

You cant time the water on these other than the preheat through a plug in clock. If the built in clock is disconnected the hot water will run on the stat so he must have moved some wiring inside. There needs to be a permanent live supply no matter what controls are fitted to LN + E on block ST10 . Ls and Lr (also on ST10) will be linked with the plug in clock in place but this link need to be removed to take external heating controls.
Easiest way is to leave the dt20 in place so you still have control over the heatbank, turn the heating to constant and turn the stat up leave it up or replace it for a DT20 without the stat.
Wire the 2 zone valves as an S plan with a 2 channel programmer or 2 programmable room stats or whatever but take the grey and orange wires of the valves back to Ls and Lr (remove the link) to switch the heating. Ls gives the grey the permanent live and when the valve motor moves (via the brown) and makes the microswitch in the valve the power is sent back the orange to switch on the boiler for ch.

 

[smileyplumber]

Im not taking sides of customer or installer here but i think what the guys meen by out thinking the installer is that if a customer is trying to suss the fault even to be helpfull sometimes it can get in the way of the installer's work/thinking proscess and affect the out come in wildly diffrent ways , this ends up with installers either making a wrong prognosis or taking alot longer than normal to solve a problem .
you will find most of quite like customers that " know stuff " because it can make explaining things easyer .
the problems arise when the customers think they know more than the installers doing the work ! abit like taking your driving test you know you can drive but on the day when the examiner is sat next to you, you fall to bits and make mistakes .

 

[mountainman]

Dancin may well be spot on there but I would have thought that the original engineer would have known that and fitted one.

Trouble is that we are in the dark and expected to come up with a simple solution based on virtually no information.

Don't think that there is a 'conspiracy theory' among heating engineers but it would seriously annoy me if I'm sorting out a problem on a system only to have the custard bleating that according to the 'Wossname Forum' the 'Flugel Valve may have a displaced pinion'.

Bet other professionals don't have this trouble; but then I don't suppose that we are regarded as professionals are we?