Hot Flow, Cold Return...advise needed please.

[Nickshafi]

Hi Plumbers,

I'm new to this forum, I have a small problem with 1 new radiator, I have very basic plumbing knowledge. At the weekend I moved a radiator in the Kitchen, spurring off an upstairs radiator from my ensuite & installed a new double convector radiator in my conservatory spurring off the pipes that the original kitchen radiator was connected to using 10mm flexi pipe & fast fix fittings. I had a few problems at the start when I started & charged the system, but after balancing & following some simple instructions found on here I have all the rads nice & hot bar 1...the new radiator in the conservatory has the flow pipe nice & hot but the return is only slightly luke warm & this is causing the radiator not to put as much heat, I mean its warm but not as blazing as the others & only the top 2 3rds really.

I have closed all upstairs & downstairs valves to try & force the water in & out of the rad, I have bled it numerous times for periods of time, just in case there was an air block in the pipes etc...after I bled for a time I went round starting upstairs & opened the rad 1/4 turn & fully opens the downstairs...

anybody have any further suggestions before I take it off the wall & check for blockages etc...I'm sure that pipe was hot the other day, but the flow was cold... Quite confusing really...

Thanks in advance peeps!

 

[Waz]

Sounds like a kink in the return pipe restricting the flow

 

[Nickshafi]

Thanks for your reply Waz.

Nah, the new pipe is accessible & visible, there are no kinks, I've push fit onto copper pipe & elbowed down from that to the rad, no sharp kinks etc, so still a mystery...

 

[derek hunter]

best thing to do is close all radiators apart from one that isnt working if it gets hot you know it isnt blocked then if so you have a flow problem either upgrade pipes or try balancing again.

 

[JamesyGoosey1]

What size pipe is the one you have teed off for your new rad?

 

[Whn1]

Did you use new valves?

 

[Nickshafi]

15mm, teed off onto 10mm legs, yes new TRV on one side & a lock shield on other, brand new & brand new rad too.

does the lock shield have a flow direction?

 

[Nickshafi]

Hi again,

Yesterday I closed both valves & removed the rad off the wall, I then got a bucket & opened both valves fully, both got great flow & red hot....so what could the problem be?

Just a bit more further info I have a TRV on the one side & the other is a standard tap style valve, the rad is a 1400x600mm double convector.

Any further suggestions?

 

[ManchesterGas]

Dereks reply 3 days ago would be where I would start.

 

[Nickshafi]

See my first post...I've done that lots of times, as I put in my first post.


I have closed all upstairs & downstairs valves to try & force the water in & out of the rad, I have bled it numerous times for periods of time, just in case there was an air block in the pipes etc...after I bled for a time I went round starting upstairs & opened the rad 1/4 turn & fully opens the downstairs...

 

[kay-jay]

Take the head off the trv and whack the pin. It will be sticking

 

[Nickshafi]

The TRV (flow) side is letting the water in fine & is red hot, the problem is the other side (return) it's only slightly above room temperature at best. But as I established yesterday when I've removed the rad & opened the valves both of them let out steaming hot water so what else could it be...are these valves bi directional?

 

[kay-jay]

There will be a L shape with an arrow on each end to indicate if it is bi-directional.

 

[kay-jay]

On the brass part of the trv

 

[Nickshafi]

The TRV has the arrows & is working fine, the other valve doesn't have any arrows...?

 

[ManchesterGas]

If you have turned the others off and it still doesn't get red hot, it sounds like a kink in a pipe or reduced flow. upgrade the 10mm to 15mm and try again.

What speed is the pump set to and how far from the rad is it?

 

[Nickshafi]

There is no kinks as I can see & have access to the pipes, all the other downstairs rads are on micro bore pipe, the pump is around 8-10ft away to the legs that lead to the rad. The pump is on 3 & as I've said the flow to the rad is red hot & flowing, it's the return end that's cool, but when I removed the rad & turned both valves on they were both red hot,

Could the rad be to big for the pump, it's 1400 x 600mm double?

 

[lbp plg & htg]

Where is the boiler - upstairs or down? Which way are the pipes run - do they go up first and then back down?

As mcr said probably best to upsize to 15mm

I 8 microbore!

 

[Nickshafi]

Boilers in the garage, I presume there's a 15mm pipe going around the floorboards upstairs, with the legs coming off to each rad, the kitchen rad is only around 4-5ft away from the conservatory also on 10mm pipe & is red hot, also this is the feed where the kitchen rad used to be & before I moved the kitchen rad it used to get nice & hot too...the only thing that's changed is the size of the rad really.

 

[lbp plg & htg]

With all other isolated does it work?

 

[Nickshafi]

Can I just make it clear cause were goin around in circles here...the flow is red hot the return is cool, the rad gets warm but not hot like all the others, I have shut off all other rads & it does get slightly hotter but the return feed is still cool. I can confirm no kinks in pipes & when I disconnect the rad & open the valves both gush out a nice flow of red hot water...so that's it...could I have a duff valve? Is my valve bi-directional? I don't think it's the pump as all other rads are piping & toastie!

 

[lame plumber]

time to get someone in who knows what they are about. all your chopping and changing has probably caused sludge to block somewhere.

 

[mfgs]

Sounds like a blockage on the return somewhere. Are you sure a bit of dirt didn't get in the pipe during installation?

 

[ManchesterGas]

I still think it is to do with pipe size...

 

[Waz]

I don't suppose there is any chance you have connected the rad to the return twice instead of flow and return (easy enough to do when connecting under floors) just a thought

 

[Best]

Does sound like poor flow.
10mm Pipe is not good to have in any great length. (try blowing through a 10 metre length of it & you will find it very resistive!)
One thing that nobody has mentioned - & it's a long shot, - is if you have a faulty rad valve. If the part inside the lockshield valve that closes- like a brass washer, - disconnects, then the valve will work only on the flow! In that case when you open the valve, plenty water will come out, but water will not go towards it as the loose "washer" will push down. Rare, but have seen this happening with a brand new L/S Peglers valve on a new system. Bit of a head scratcher, but knew it was the only thing possible as pipework was spot on.

 

[Leo21]

Get someone in, sounds like a really unusual and difficult problem.

 

[Best]

When anyone (especially non plumbers) has problems with a rad not heating up fully after they have connected into a system, or extended pipes, then I always think pipe size overloaded & usually the dreaded word "microbore" appears!
If joining 10mm to existing 15mm pipes, I would prefer the 15mm carried on, so to reduce the overall run of 10mm.
Remember that even just going into a smallish room with f&r to a rad will often be well in excess of 10 metres combined length, which is a lot.

 

[Nickshafi]

The micro bore only runs around 2.5 metres up & down from the 15mm it's virtually in exactly the same place as where I moved the kitchen rad was originally just the the other side of the wall, all the downstairs rads are on 10mm, it's how the house was built.

I doubt a difficult problem as the rad does get warm but not hot & as its in the conservatory I would like it to get nice & hot. I suspect either faulty valve or airlock...anyways ill change the valve & see what happens.

cheers for all your comments guys.

 

[kay-jay]

hang on a minute, is this rad bigger than the old one? and is it fed from the pipes which also supply another rad? if so then this is called piggybacking and usually one rad heats up to the detriment of the other from the other. this is bad practice.

 

[Nickshafi]

No, I've piggybacked off the small ensuite rad which runs off 15mm for the newly positioned kitchen rad, the kitchen rad is getting plenty of heat out piggybacking from upstairs....the new rad is being run off the pipes that kitchen rad was previously run from...if you get me.

 

[Leo21]

The micro bore only runs around 2.5 metres up & down from the 15mm it's virtually in exactly the same place as where I moved the kitchen rad was originally just the the other side of the wall, all the downstairs rads are on 10mm, it's how the house was built.

I doubt a difficult problem as the rad does get warm but not hot & as its in the conservatory I would like it to get nice & hot. I suspect either faulty valve or airlock...anyways ill change the valve & see what happens.

cheers for all your comments guys.

If its not a difficult problem fella why can't you fix it? Everyone on here's given you the usual suspects of the problem. Perhaps you should have got a professional in. It's obvious you've done something wrong and you don't have the ability or the knowledge to fix it.

 

[dancinplumba]

well said leo, i agree 🙂

 

[Nickshafi]

I am thankfull for your help & I take your advise on board, I'm capable of bleeding & balancing, what I wanted more clarification on was if the valves were in fact bi-directional &/or if I'd put a radiator that is to big for the system.

Just to inform you, a proffesional quoted me £400 & 2 days work to do the job I did in half a day, he told me that my upstairs carpets needed pulling up & all sorts & also I had heat cover up until 2 months ago, an engineer came out as one of the rads weren't getting hot, he blamed sludge which isn't covered on the plan, he said his company charge £500 for a power flush, when he went I watched a couple of YouTube videos about TRV's sticking & voila...removed TRV, tapped the pin & she has worked fine ever since.....

so excuse me If I don't hold out much trust in professional trades people, I'm a young bloke quite capable of intermediate DIY...I am proud that I saved £400 & completed the work myself, I only wanted to know if there's a simple fix or if it was a common problem, I don't need sarcasm, as I said if this is as hot as its gonna get then so be it...ill change the valve anyway & see how it goes.

Thanks again to all who tried to help,

 

[Dannyparty92]

You say your heating is fed off 10mm? Then your new radiators need there own feeds directly off the heating manifold.

 

[boilerrepairs]

Hi Plumbers,

I'm new to this forum, I have a small problem with 1 new radiator, I have very basic plumbing knowledge. At the weekend I moved a radiator in the Kitchen, spurring off an upstairs radiator from my ensuite & installed a new double convector radiator in my conservatory spurring off the pipes that the original kitchen radiator was connected to using 10mm flexi pipe & fast fix fittings. I had a few problems at the start when I started & charged the system, but after balancing & following some simple instructions found on here I have all the rads nice & hot bar 1...the new radiator in the conservatory has the flow pipe nice & hot but the return is only slightly luke warm & this is causing the radiator not to put as much heat, I mean its warm but not as blazing as the others & only the top 2 3rds really.

I have closed all upstairs & downstairs valves to try & force the water in & out of the rad, I have bled it numerous times for periods of time, just in case there was an air block in the pipes etc...after I bled for a time I went round starting upstairs & opened the rad 1/4 turn & fully opens the downstairs...

anybody have any further suggestions before I take it off the wall & check for blockages etc...I'm sure that pipe was hot the other day, but the flow was cold... Quite confusing really...

Thanks in advance peeps!

you have an air lock on the return pipe from the radiator.

 

[Whn1]

you have an air lock on the return pipe from the radiator.

Quite clearly not as he's pulling hot water through both.

 

[Whn1]

Everything possible has been mentioned, the job needs looking at.

 

[Best]

Everything possible has been mentioned, the job needs looking at.

Trouble is, he doesn't have much trust in professionals.

 

[Nickshafi]

I'm happy to try a new valve first, then ill make the decision to either live with it hottish...or get a Proffessional to look at it...it's in the conservatory & we don't sit much out there & summers coming.

 

[Whn1]

Can't see it being the valve. Good luck

 

[mfgs]

I am thankfull for your help & I take your advise on board, I'm capable of bleeding & balancing, what I wanted more clarification on was if the valves were in fact bi-directional &/or if I'd put a radiator that is to big for the system.

Just to inform you, a proffesional quoted me £400 & 2 days work to do the job I did in half a day, he told me that my upstairs carpets needed pulling up & all sorts & also I had heat cover up until 2 months ago, an engineer came out as one of the rads weren't getting hot, he blamed sludge which isn't covered on the plan, he said his company charge £500 for a power flush, when he went I watched a couple of YouTube videos about TRV's sticking & voila...removed TRV, tapped the pin & she has worked fine ever since.....

so excuse me If I don't hold out much trust in professional trades people, I'm a young bloke quite capable of intermediate DIY...I am proud that I saved £400 & completed the work myself, I only wanted to know if there's a simple fix or if it was a common problem, I don't need sarcasm, as I said if this is as hot as its gonna get then so be it...ill change the valve anyway & see how it goes.

Thanks again to all who tried to help,

Do you think maybe the fact that he said it was going to take 2 days is because he was going to do it another way? Possibly the correct way to get it working? Just putting it out there....

 

[Dotty]

Said he doesn't trust professionals yet has the front to ask our advice?

Dont take us for muppets!

Thread closed.