No hot water but central heating fine

[carrpaul]

hi there is this a new boiler ? what valves are on the system ( make ) and pump fixed speed or A rated type modulating . might be time to seal the system if your having to shift a blockage , could do with a ton more info on system history age of parts . did you have the sparky and gsr guy looking at this together might help ,

 

[DBatchelor]

hi there is this a new boiler ? what valves are on the system ( make ) and pump fixed speed or A rated type modulating . might be time to seal the system if your having to shift a blockage , could do with a ton more info on system history age of parts . did you have the sparky and gsr guy looking at this together might help ,

Whole system is approx 3 yrs old but it's not been working for a while now. Valves are honeywell 2 ports, pump is a grundfos 3 speed. No, I had the plumber out first with the sparky a week after.

 

[Dotty]

If you've an s plan and it works fine on the heating 2 port but not the hw 2 port which you say is opening fine and sending the signal to the boiler which fails to fire due to lack of movement of water then you're looking at the cylinder.

Look for a balancing valve at the cylinder, make sure that's open at least 1/2 to 3/4 turn. Open it fully as a test firsthand.

Gently crack the nut on your flow to the primary coil and make sure that you've got water coming out. Make sure you don't undo it fully, just a couple of turns to loosen it slightly will do. Then do the nut back up. Make sure that you've plenty of towels down.

If it doesn't go after that you'll need a decent heating engineer in. Certainly not an electrician!

 

[DBatchelor]

If you've an s plan and it works fine on the heating 2 port but not the hw 2 port which you say is opening fine and sending the signal to the boiler which fails to fire due to lack of movement of water then you're looking at the cylinder.

Look for a balancing valve at the cylinder, make sure that's open at least 1/2 to 3/4 turn. Open it fully as a test firsthand.

Gently crack the nut on your flow to the primary coil and make sure that you've got water coming out. Make sure you don't undo it fully, just a couple of turns to loosen it slightly will do. Then do the nut back up. Make sure that you've plenty of towels down.

If it doesn't go after that you'll need a decent heating engineer in. Certainly not an electrician!

Makes sense, they share a flow from the boiler so the obstruction has to be in or around the cylinder.

Not entirely sure what (or where) a balancing valve is, I did (slightly) open the air release on the primary coil which let water out, no air.

 

[DBatchelor]

Would it be worth draining and then refilling the system to see if that dislodges anything? Or do I run the risk of causing more damage/introducing airlocks by doing this?

 

[carrpaul]

put system on to h/water only and unplug flow switch click system on and then link out flow switch and see if boiler fires, could be week pump / blocked pump. scrub all this , just get plumber in go on baxi site and find installer .

 

[DBatchelor]

put system on to h/water only and unplug flow switch click system on and then link out flow switch and see if boiler fires, could be week pump / blocked pump. scrub all this , just get plumber in go on baxi site and find installer .

Thanks for the reply.

I don't think it's the pump tho because that works fine for the Central heating, or am I wrong?

I think you're both right tho, this is a (potentially expensive) job for a heating engineer.

Thanks again for all your help, and I'll update once it's resolved as to what exactly it was, in case anyone else has the same problem.

 

[Pipes Plumbing]

Shouldn't be a horrendously expensive job for a decent engineer to diagnose & resolve for you, certainly not as expensive as parts being changed in error or something going horribly wrong...

Also not as bad as you taking the case off the boiler and breaking the law. Please don't do it, just get a decent heating engineer in. One of the local member may well be able to help you if you pop a post in the 'Looking for a Plumber section'

Good luck getting it resolved!!

 

[DBatchelor]

Shouldn't be a horrendously expensive job for a decent engineer to diagnose & resolve for you, certainly not as expensive as parts being changed in error or something going horribly wrong...

Also not as bad as you taking the case off the boiler and breaking the law. Please don't do it, just get a decent heating engineer in. One of the local member may well be able to help you if you pop a post in the 'Looking for a Plumber section'

Good luck getting it resolved!!

Appreciate the advice, I'll see if I can find someone.

For what it's worth I've just checked and there is flow into and out of the primary coil, so I'm stumped (again!!)

 

[JamesyGoosey1]

What do you mean by dry fire, that usually only applies to combis or system boilers that can sense via the pump that there's no resistance.A normal open vented boiler wont detect anything like that.Do you mean it overheats and shuts off on hw.

The Baxi solo and the promax (same boiler) they have dry fire sensors on them and they are fitted to open vented systems