Central heating help?

[charltjr]

Hopefully quick question around whether I need a plumber or I can fix this myself.

Heating is working but only on upstairs radiators, we also have hot water in the tank. This is a standard old school pumped system not a combi boiler.

I was thinking it might be a jammed pump or airlock, have bled all the radiators and they’re full of water. Pump is definitely running, although I suppose the impeller might have sheared off? I’ve noticed there is water dripping from the air relief valve thingie (technical term) and the pump sounds a bit aerated. I think I could probably just slap a new valve on it as there’s a cutoff for it, which could then let the system self bleed if it needs to? Or am I just talking twaddle and I’d be better off getting someone who knows what they’re doing out? Any advice much appreciated

It’s clearly been dripping for a while and needs changing:

Noisy:

 

[Ol’ Tarby!]

If you turn the upstairs radiators off, do they come on downstairs?

 

[charltjr]

There’s a good question, I’ll try that now.

 

[charltjr]

If you turn the upstairs radiators off, do they come on downstairs?

Yes, immediately I switched off the upstairs rads all of the downstairs ones started heating up, they're fully up to temp now. I wasn't able to turn off one of the upstairs rads as the valve is stuck but five of the six upstairs ones are off.

 

[Ol’ Tarby!]

It suddenly just started happening? Or you had anything else done lately?

 

[charltjr]

No work done recently, I did notice the other week that the front room rad was taking ages to warm up at all but the others were fine. Only noticed today that the downstairs rads were all stone cold. So I'd guess whatever it is has been happening gradually over the last few weeks, but we've not touched the heating.

 

[Ol’ Tarby!]

It could be a balancing issue maybe? I'm a bit out of ideas beyond that though

 

[charltjr]

The other thing which I've just noticed is the floor in the airing cupboard is damp, and I definitely don't remember those water marks on the air bottle before, so I think there's been water dripping out of there for a while. It must be linked somehow?

There's no water leaking from the boiler itself and it's not a pressurised system or anything. Confused.

 

[R3k1355]

Have you tried bleeding air out of the radiators?

Deffo need that air valve thingy replaced, is it supposed to be at the top of the system bleeding air out?

 

[charltjr]

Yeah there's no air in the rads. That's what I understand the air bottle is for. I think I'll just grab one from Screwfix and swap it out. Looks like a piece of piss to replace.

 

[sburrell93]

When you turned off the upstairs radiators, did the downstairs ones take longer to heat up than usual? Could be a blockage building up somewhere in the downstairs loop which means they're not getting any hot water unless the upstairs is closed off and it's forced down through them.

No idea how that would relate to the leaking air eliminator though!

 

[charltjr]

Nope, they got hot really quickly. I wonder if the fact it's leaking was enough to throw the balancing of the system out somehow, but that would be a total guess.

I've been doing some youtube-ing and it seems like I can just cap off or isolate the valve in the short term anyway, it's only to bleed air out and as it's full of water there clearly isn't any air in the system - or at least none which is able to reach the valve. Isolating it will prove if it was actually the problem or a symptom. I'll swap it and see how it goes.

 

[Rob G]

A leaky air vent wouldn't cause balancing issues, could be that your pump is in the way out if it's only started happening recently.
When you shut off upstairs you're moving less water about so will produce more pressure to overcome the higher losses to the downstairs rads.

 

[charltjr]

Yeah it's definitely not the cause, I've isolated it now with the cutoff valve and the rads are still cold downstairs with the rads on upstairs.

There are cutoff valves either side of the pump too, thank god, so I could probably swap that out myself but it will be a bugger if that doesn't fix it. Hmmmm. I guess I'll have ruled it out for not much more than a plumber's callout fee.

 

[sburrell93]

Have you checked the header tank in the loft? Listening again that pump sounds like it's pulling air through, as if there isn't enough water in the header tank. When those air vents lift to let air out they'll naturally let a little bit of water out too and if it's been constantly lifting then it would explain the water marks down it.

 

[charltjr]

Good shout, I’ll have a look tomorrow

 

[Cookson]

Bump on this. My kitchen rad didn't seem to be warming up. I've taken off the thermostatic valve, and its got slightly warmer, but only on the top bit closest to the inlet side. Other side and bottom are fairly cold. I'm thinking it needs pulling off and cleaned out as may be full of sludge, or do we think I should open the stop valve at the other side?

 

[R3k1355]

If it is full of sludge are you prepared to clean it out yourself?

 

[Rob]

Bump on this. My kitchen rad didn't seem to be warming up. I've taken off the thermostatic valve, and its got slightly warmer, but only on the top bit closest to the inlet side. Other side and bottom are fairly cold. I'm thinking it needs pulling off and cleaned out as may be full of sludge, or do we think I should open the stop valve at the other side?

Buy a new rad whilst you’re at it. Unless it’s something fancy they cost peanuts

 

[Cookson]

Buy a new rad whilst you’re at it. Unless it’s something fancy they cost peanuts

Do they costs less than washing it out?

Or do you mean a new one would be more efficient? Are they standard sizings? I don't want to be fuckin about cutting pipes and s**t.

 

[R3k1355]

Yea they're usually standard sizes, come in various heat outputs.

No idea how to figure out what one you've got already.

 

[green]

That pump should be almost silent. There’s definitely a load of air in your system.
I’d be changing that ARV/ air valve. Once the air is out the pressure in the system will return to normal.

 

[Rob]

Do they costs less than washing it out?

Or do you mean a new one would be more efficient? Are they standard sizings? I don't want to be fuckin about cutting pipes and s**t.

So

a) it’ll work better as you’ll never get all the sludge out

b) you’ll remove any chance of the sludge in it eventually ending up back in to the system

c) it’ll be nice and clean looking, depending upon how old it is, they often go a bit manky.

And yes, standard sizing, measure between the incoming valves.

 

[Archtronics]

If It’s an old house they will be imperial measurement so new ones won’t fit perfectly so will require the pipes bending.
Fine if it’s a 10mm system if not I wouldn’t bother.

 

[Rob]

If It’s an old house they will be imperial measurement so new ones won’t fit perfectly so will require the pipes bending.
Fine if it’s a 10mm system if not I wouldn’t bother.

Fair one. It’s an easy enough measure up!

 

[Cookson]

Looks like a 900mm x 600mm rad, and the piping looks to be 10mm. So would it just be a case of literally swapping new rad for old rad, or do I have to swap fixtures too?

Just seems a bit of a waste of £60 for a new rad when I can wash the old one out.

 

[gez 172]

It won’t feel like a £60 waste when you put the heating on and feel the heat output difference.

 

[charltjr]

Sorry just realised I've not updated, I've not actually got round to doing anything about this other than permanently turning off a couple of upstairs rads to get the downstairs radiators working again. The header tank in the loft is fine.

It does seem to make sense that it's an issue with air in the system or the pump is screwed. I opened up the isolator to the air valve again after a few days and it had a good old hiss as the air came out. The radiators and their valves are all old and knackered, honestly the whole system other than the boiler needs binning and starting again sooner rather than later, but I will definitely replace that air valve over Christmas and see if it helps.

 

[yeecup]

i have cover with british gas, pay monthly for central heating cover, worth every penny imo ive used them a few times now when my heating has stopped working, from valves to pumps and they service it annually. loads of smaller companies offer the same service, maybe worth looking into.

 

[Flat Eric]

Looks like a 900mm x 600mm rad, and the piping looks to be 10mm. So would it just be a case of literally swapping new rad for old rad, or do I have to swap fixtures too?

Just seems a bit of a waste of £60 for a new rad when I can wash the old one out.

Post a picture up of the rad in question.

 

[Cookson]

Post a picture up of the rad in question.

So you can chortle at my 1983 build, yellowed by ciggie smoke, kitchen clothes dryer?

No ta.

 

[Flat Eric]

So you can chortle at my 1983 build, yellowed by ciggie smoke, kitchen clothes dryer?

No ta.

No not at all. So I can see the valves which are on currently and see if it can be a straight swap.

 

[charltjr]

I changed the bottle air valve this afternoon,, anyone have any idea how long it should take to bleed the air out? I’m not sure if I should give it a few hours or a few days. Pump is still noisy and flow to the downstairs rads is still crap so I guess the next step would be to check the pump.

 

[Rob]

I changed the bottle air valve this afternoon,, anyone have any idea how long it should take to bleed the air out? I’m not sure if I should give it a few hours or a few days. Pump is still noisy and flow to the downstairs rads is still crap so I guess the next step would be to check the pump.

Is the pump adjustable? Sometimes the grunfoss units have a little tab to adjust. Try turning it up if possible?

 

[charltjr]

It is adjustable, but it’s on maximum already.

The pump seems maybe slightly quieter today, maybe it needs a few heat cycles or to just run for a while, but fingers crossed that the system is bleeding itself. It’s probably just wishful thinking and the pump is actually failing, it seemed quiet on startup but then got gradually noisier over the next 20 minutes which seems like a bit of a concern.

Given the cost of getting a plumber out, and that a straight swap replacement is £100, I may just try to swap it myself next week if nothing has improved. I’m comfortable with the wiring side of things and there are isolation valves either side of the pump so it’s firmly in “how hard can it be?” territory. That always goes well, isolation valves which haven’t been touched for ages never fail

Grundfos UPS3 15-50/65 Domestic Heating Circulator 230V

Order online at Screwfix.com. null FREE next day delivery available, free collection in 5 minutes.

www.screwfix.com

 

[charltjr]

Yeah..... so the thing about isolation valves, the key thing about valves which are there to isolate something, is they’re not much use if they don’t isolate that thing.

Off to YouTube I go to decide if I fancy doing a partial drain down and refill or if I’m just going to call a plumber to sort it all out

 

[Rob]

Yeah..... so the thing about isolation valves, the key thing about valves which are there to isolate something, is they’re not much use if they don’t isolate that thing.

Off to YouTube I go to decide if I fancy doing a partial drain down and refill or if I’m just going to call a plumber to sort it all out

Freeze kit?

 

[charltjr]

Freeze kit?

I didn’t even know they existed!

Freezing a pipe instinctively seems like a bad thing, but seems like they’re pretty widely used. Thanks for the tip.

 

[Rob]

I didn’t even know they existed!

Freezing a pipe instinctively seems like a bad thing, but seems like they’re pretty widely used. Thanks for the tip.

You’re welcome. As you had a pump, the system isn’t under mains pressure, so get it good and cold and crack on.

Have a hosepipe and some sort of make shift fitting at the ready mind you, just in the event you don’t complete the work in time you can drain the bugger if it starts to thaw

 

[charltjr]

I fixed it!

By which I mean, "I gave up and phoned a plumber".

The pump was buggered. The new pump on minimum setting is working better than the old pump was on maximum.

The system is a badly plumbed, out of date, sludged up mess which is in need of redoing pretty much from scratch, but we knew that already. Happy days, warm house.