Reverse circulation problem with radiators

[GSM]

Hi, I'm new to this forum, so hope I'm doing things correctly.

I have a problem with my heating system in my new house, which I have recently just moved into, and hoping someone can help me out.

Unfortunately I'm not from a plumbing background and thought it would be useful to post this on this forum to seek some advice.

Basically, my plumber has only used one common return pipe from the hot water cylinder in my hot press to my boiler and T'd everything off this one return pipe, meaning that when I call for any zone, eg. my hot water zone, I am finding that my radiators are heating on the return side (reverse circulation). This will circulate through all the radiators depending on how long the particular zone is turned on for. (I have found this out as I have photographs of all the pipework before finished floor screeds where laid).

I now know that separate return pipes should have been taken out with nothing T'd off them, and know that the plumber has taken shortcuts by not putting this extra pipework in.

Unfortunately the plumber has left me with this problem and doesn't want to know and has assured me that there is nothing wrong with the pipework below my floors!

I have spoken to a friend who has done plumbing work in the past, and he has said that I have two options -

1. Fit non-return valves on the return side of all rads, and a non-return valve on the return pipe to separate ground & first floors radiator zones, or

2. Cut open the floors and fit new return pipework.

Option 2 would cause alot of hassle for me and my family, not to mention the hugh expense, I therefore have tried option 1 and sourced spring loaded non-return valves and had them fitted last weekend. Unfortunately they haven't sorted the problem, although they do stop the reverse circulation. I have found that the spring non-return valves have created too much resistance and my pump isn't able to pump the water around all the circuit, also they are very noisey when the water passes through them. These valves where fitted on the vertical copper pipework coming up from the floor and are exposed as I was told they may require to be changed in the future and therefore its better to keep them exposed.

I have have 9 radiators upstairs of which the pump was only able to heat 7, and I have 13 downstairs with a zone of underfloor heating.

I have spoken to my plumbing supplies this week, and they have tried to source a valve with a lighter spring which wouldn't create as much resistance and noise. Unfortunately, they weren't able to source one, but have suggested using the flap type non-return valve.

Can this be fitted on the vertical copper upstand pipe, or would they not operate properly? and would there be any noise from them? If they can only be fitted horizontally, if a hole be cut in the floor screed and the return pipe exposed at every radiator and valve fitted, can it be covered over with floor screed again? or do the valves need to be exposed for future maintenance or replacement?

I would greatly appreciate any help and advice on this problem, or even if anyone has experienced anything like this before and the best solution to solve it.

Kind Regards,

GSM.

 

[Simon F]

is there no possibility of re routing the return from the hot water cylinder back to the boiler so that it is the last connection?

 

[Mike Jackson]

If you've got the pictures then you have the proof. If the original plumber refuses to put right the faulty work then commision a report from a fully qualified heating engineer, get the work done and take the original plumber to court. Fitting non return valves is a bodge and should only be done as a last resort. Why should you suffer because a tradesmen you have paid doesn't know his job?

 

[GSM]

Hi, thanks very much guys for the advice.

A new return pipe could be possible although I think the plumber has T'd off the single common return pipe in different locations as it passes through the house, so I would have to pick up the returns of the other radiators aswell, which would mean cutting up alot of floors.

Fortunately, I don't have many floor finishes down as yet. If I thought fitting the non-return valves would work, I would consider trying this as I don't want to create alot of hassle/disruption for my family since we are living in the house, although I am very disappointed in the plumbers work and the situation he has left me with.

Would the flap type non-return valves fitted on the horizontal pipework under the floors work? and would they ever need replaced in the future? Would it be ok to insulate the valves and screed over them again?

 

[Simon F]

A new return pipe could be possible although I think the plumber has T'd off the single common return pipe in different locations as it passes through the house, so I would have to pick up the returns of the other radiators aswell, which would mean cutting up alot of floors.

no need to undo everything, just a new return from the hot water cylinder, disconnect the current return from where it connects to the cylinder, run a single return from cylinder back to boiler to be teed in as the last connection with the exception of any bypass fitted.

 

[northstar]

hi gsm what area do you live in ? as someone local on here may be able to help you

 

[SimonG]

Welcome along

 

[Unregistered]

Hi, thanks very much guys for the advice.

A new return pipe could be possible although I think the plumber has T'd off the single common return pipe in different locations as it passes through the house, so I would have to pick up the returns of the other radiators aswell, which would mean cutting up alot of floors.

Fortunately, I don't have many floor finishes down as yet. If I thought fitting the non-return valves would work, I would consider trying this as I don't want to create alot of hassle/disruption for my family since we are living in the house, although I am very disappointed in the plumbers work and the situation he has left me with.

Would the flap type non-return valves fitted on the horizontal pipework under the floors work? and would they ever need replaced in the future? Would it be ok to insulate the valves and screed over them again?

This is the way to do it, think of the existing return as your return for the heating, and run a new return in for the cylinder, capping off the 'heating return' which is under the floor by the cylinder. Then tag it back in as close to the boiler as possible. Best solution providing you can find a route for the new return.

Is it a tank feed open vent system, or is it pressurised which needs a filling loop to fill up? If it's pressurised you'll have a lot less limitation on re-routing the new pipework, like maybe up into the loft and back down etc (i'm presuming it maybe a bungalow if the pipework is chased into the floor?)

Sam

 

[GSM]

Hi, sorry for not getting back sooner. I'm from N.Ireland. My heating system is an unvented pressurized system and my house is two storey with precast slabs and sand/cement screed floors to first floor.

Since I was on this forum last, I have had another plumber look at my problem. He has suggested providing a new return pipe to the boiler (as you guys have suggested to me on this forum). He advised that the common return pipe be cut off at first floor level where it drops vertically to a service cupboard below, and has said that a new return pipe be tracked into floor from this point into my hot press to my cylinder which is across the bathroom floor and connected to the existing return pipe which will serve the first floor heating zone.

He has also suggested connecting the existing return from the cylinder to the vertical return pipe in the service cupboard which will serve as the return for the ground floor and also putting a stop end on this return beyond the last radiator before it passes outside to my boiler.

He then has suggested providing a new return from my cylinder across a first floor bedroom floor, down the inside of an internal cavity wall which isn't insulated (using a flexible pipe), bringing the return through a short section of floor on the ground floor and through an external cavity wall and then underground across my driveway to the boiler situated in my garage.

I know this means alot of work, but at least the work can be confined to only a few rooms in my house which thankfully I haven't tiled or carpeted as yet. From all your advice on this forum and from speaking to another plumber, I feel that this is a better solution that fitting valves under my floors.

Does this all make sense? and should it work and solve my problem?

Many thanks,

GSM.

 

[PDL]

If as u say he has tapped into the return at multiple points your only solution is new return pipe for the hot water and make connection of hw return as close to boiler as possible follow 3t rule which creates a type of resistance to prevent minimise backflow risk, if how ever and im not suggesting this is for u he has 1 loop for downstairs and 1 loop for upstairs u could consider 2 port valves as u would only have to cut in a small area of pipe and just run electrical cable from this point to wiring center insuring that the only open when heating is on and are placed only on ch returns its the same as zoneing off areas larger than 150 sq m but for different purpose these valves are farely cheap and do not require expensive cable seek advice on materials and design if u are not compotent