Hot water problems, any help appreciated

[thebaronn]

Hi all, I have a problem with my DHW system which is not as old as the house, but it seems to behave that way! I'm looking for some advice on a problem I have with HW; ideally I'd like to know what's wrong with it, what needs replacing/repairing and how much it is likely to cost (parts and labour). Here is the problem...

First of all the setup, it's a typical system for when the house was last refurbished; cold and expansion water tanks in the loft, hot water cylinder w/immersion in the airing cupboard, boiler in the kitchen. I have had several other (hopefully unrelated) issues over the last year or so, so have ended up replacing the 3 position valve, room and tank stats, as well as the programmer (which is separate to the boiler). Components are pretty standard, Honeywell valve and tank stats, Horstmann programmer and room stat. The boiler is an Ideal Classic FF360.

We seem to have no problems with the CH (famous last words!). The new programmer and room stat also seem to be working fine (we also have some rad stats, but tend to leave them on full or off). However, when we programme HW, the burners in the boiler fire up, stay on for a couple of minutes and then cut out. We have been relying on the immersion for the last few days for HW, which is working fine and seems to be giving us a full cylinder's worth.

Any ideas would be gratefully received. My thoughts so far:-

• Could the plumber have wired the 3 position valve incorrectly/loose connections?
• Is a stat in the boiler malfunctioning?

As I say, any advice appreciated, cheers.

 

[Dotty]

Could the plumber have wired the 3 position valve incorrectly/loose connections?

Probably. Although it sounds more like it's been incorrectly piped.

Is a stat in the boiler malfunctioning?

No. Don't touch it.

 

[thebaronn]

Probably. Although it sounds more like it's been incorrectly piped.



No. Don't touch it.

Cheers croppie.

The valve was put in exactly the same way/place as the one it replaced, so piping should be OK. I guess I can check the wiring, although I have been told that in the HW mode the 3 port valve does't need to work, it's already open in the HW port .

 

[Reg Man]

Get a qualified engineer in. Sounds like a water circulation problem on the heating flow and returns to your HW vessel.

 

[Ermintrude]

Cheers croppie.

The valve was put in exactly the same way/place as the one it replaced, so piping should be OK. I guess I can check the wiring, although I have been told that in the HW mode the 3 port valve does't need to work, it's already open in the HW port .

Bypass or balancing valve on cylinder incorrectly adjusted or air lock .

 

[thebaronn]

Thanks Reg Man and Ermintrude. Just another thought, I have made sure there is no hot water in the cylinder (left over from having the immersion on). I have now set the 3 way valve to manual (open) and switched on the HW only. My thinking is that the rads should heat up, but, if the valve is where the problem is then I should not get any HW (unless it is the cylinder)? With the valve set to manually open, the boiler at least now fires up and stays on. Will give it a few minutes to see if I get any HW. The pipe to the cylinder is now getting slowly warm, unless that's heat transference.

 

[thebaronn]

I have just checked the wiring to both the tank stat and the 3 way valve, and it looks good
(ref Y-plan system). Honeywell tank stat L641A, Honeywell 3 way diverter valve,
both wired to standard 10 terminal junction box. Tank stat to terminal box as
follows (C to 6, 1 to 8, 2 to 7). Valve to terminal box (blue to 2, green/yellow
to 3, white to 5, grey to 7, orange to 8). Looks like it may therefore be an
airlock in the cylinder/blocked cylinder. Sound plausible? Any suggestions to
prove/clear this?

 

[Ermintrude]

Close all possible routes back to boiler other than through cyl. If flow and flow and return almost same temp u have the extraordinarily strange cylinder and need a new one? Couldn't be a burst coil?? Water would be poop ? ?

 

[thebaronn]

Morning Ermintrude. "Close all possible routes back to boiler other than through cyl" isn't that what I did by just enabling HW only i.e. flow is through heating coil in cylinder only; set by 3 way valve? Sadly it's no possible to check flow and flow return temp difference as boiler cuts out after only a minute or so (if that).

 

[Ermintrude]

Is there a bypass? Pipe from 3 port valve side of pump on to return with a vale in the middle?
Is there a drain off above boiler? If so connect ur garden hose and blast some , lots of water in.... Until is running out of overflow at back of house! Careful not to flood loft! Also stupid question have u vented all pipework and pump?

 

[thebaronn]

Hi Ermintrude, no bypass I'm afraid.

 

[dancinplumba]

Time to call the professionals in me thinks

 

[PlumbBobBob]

if you put a request here [DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL] putting your general location, there may be someone from the forum who is close to you

 

[thebaronn]

Time to call the professionals in me thinks

:lol: That is the plan dancinplumba, just want to make sure that they can hit the ground running / look at the right thing / I have not overlooked something obvious that I can tackle myself. I've had issues in the past with "swap and hope" tactics

 

[Dotty]

With all due respect I'd rather the person i go do a job for doesn't research his/her problem on t'internet. Nothing worse than "This is what the problem is....."

Especially because they're usually wrong.

Get someone off here, they'll put eyes on and tell you fairly quickly what's wrong. Then repair it for the appropriate fee.

 

[thebaronn]

Appreciate that croppie, I'd never tell anyone how to do their job based on a bit of forum research, one of my pet peeves! I'm just trying to educate myself so that I can at least understand the possible causes of the problem (and prepare myself financially for the possible outcomes...). There may have been an easy fix, but it looks like we have exhausted that possibility. So, as you suggest, my next step is to get someone to look at it. Really appreciate all the comments fellas, I have learnt a lot (y).