Blocked Pipe.

[MickBrown]

Changed some radiators in a customers property. The property is a bungalow with all the pipes under the floor (mainly concrete). It looks like 2 circuits one with 2 radiators and the other with 9 radiators. It refillled okay but when I put the boiler back on I couldn't get most of the radiators to heat up. The circuit with 2 radiators was fine but the other circuit only what appears to be the first radiator heats up, if i switch off all radaitors and turn one on at a time only what appears to be radiators 2 and 3 get very luke warm 4nto o9 stay cold. I attached a hose to the radiator that appeared to be the last in the series and got good hot water flow but when the radiator put back to normal it does not heat up. It looks like a blockage on the return somewhere between radiators 1 and 2. This part of the system is much older than the rest which I think has been added to when extension work was done.

What I plan to do is attach a hose to the vent on the second radiator, close all radiators and open the flow to this radiator to check flow okay. If okay close the flow and open the return and then open the flow and return on the first radiator. If the return between the first and second radiator is blocked then the nothing will come out of the second radiator vent, if it is not blocked then some water should come out of this vent. If no water comes out of this vent then I am going attatch a hose between the vents on the first and second radiator, close the flows on these and open the returns, open flow and return on third radiator. My theory is that if the blockadge is between 1 and 2 then the flow will go through rad 3 and then into the return of rad 2 through the pipe to the 1st rad and then out through it's return. If this is successful then I will try and flush mains water through the return pipe between 1 and 2, no problem flushing in return direction but if I try the other direction I will have to block off the vent and cold feed. If this does not work then I will have to get somebody with power flush equipment to try and clear it as I do not have a power flusher.

Should all my investigations prove that there is a blockage then I think the only option is to run a surface pipe from the return on rad 2 to the return on rad 1 to bypass it, this does not look too difficult.

Anybody got any thoughts on my plans and any other tips would be appreciated. Thanks.

 

[Howsie]

On first inspection I think you're on the button.

Have you dosed it?

 

[SimonJohns]

Your on the right track. You'll get there

 

[MickBrown]

I haven't put anything as yet but probably try some system cleaner when I go back.

 

[Howsie]

1.5 times normal pressure is adequate.

 

[JCplumb]

I had something similar a couple of weeks ago, took me 2 days to get all the rads to heat up.
Not got a power flusher but it was a combi so had decent pressure to individually disconnect each rad, bung em then use an old bodged washing machine hose fitting onto some hose to connect to the TRV then the lockshield of each one, it was a manifold setup so I ran each connection for about 10 minutes to ensure any airlocks or blockages were pushed through.
I had a mate in the loft opening the filling loop when needed to keep the flow going.
It was a royal pain in the arse to be honest, there's just no incentive for the water to reach the further radiators especially when the installer had put a loop from flow to return about 3 foot from the boiler, I know you have to do this for safety incase all rads are closed, but a gate valve on it would have been handy!

 

[dontknowitall]

Assuming it's an airlock:

If you have a wet vac it's easier and drier to do this method but if not a couple of large towels and one or two containers will do the same.

Turn on heating and wait for warmth.

1. Close both valves of suspect radiator.
2. Bleed top of rad then open one valve. If water flows, close valve and open other valve. If water flows then no airlock but this should confirm there is one. If you're lucky this might be enough to clear it.

Assuming bleeding doesn't work then close both valves and bleed valve.
Attack suspect end (e.g. lockshield if this end is cold and other end is warm).

Towel(s) under valve and container too (or wet vac if you have one). Then open nut from rad to valve and drain till water goes warm. If you hear gurgling, feel air coming through (with the water) then warm water you know you've fixed the problem.

Alternatively, close lockshield and open nut on pipework and extract water from this point as other nut will be draining radiator as well - but rather messy and risky this way. This stops water falling from radiator but it's much more difficult to control the water spill.

Tip: you don't need to undo the nut completely - there'll be plenty of water coming out! Instead free it with a spanner, then use your fingers. Keep as much thread attached as possible and pull pipe away from fitting. (A couple of millimeters all round the pipe will give plenty of flow for this exercise.)

With 10mm pipe you can be braver but best to keep safe with 15mm pipe.

Finally I hope I'm not teaching you to suck eggs!!

 

[southcoastboile]

Changed some radiators in a customers property. The property is a bungalow with all the pipes under the floor (mainly concrete). It looks like 2 circuits one with 2 radiators and the other with 9 radiators. It refillled okay but when I put the boiler back on I couldn't get most of the radiators to heat up. The circuit with 2 radiators was fine but the other circuit only what appears to be the first radiator heats up, if i switch off all radaitors and turn one on at a time only what appears to be radiators 2 and 3 get very luke warm 4nto o9 stay cold. I attached a hose to the radiator that appeared to be the last in the series and got good hot water flow but when the radiator put back to normal it does not heat up. It looks like a blockage on the return somewhere between radiators 1 and 2. This part of the system is much older than the rest which I think has been added to when extension work was done.

What I plan to do is attach a hose to the vent on the second radiator, close all radiators and open the flow to this radiator to check flow okay. If okay close the flow and open the return and then open the flow and return on the first radiator. If the return between the first and second radiator is blocked then the nothing will come out of the second radiator vent, if it is not blocked then some water should come out of this vent. If no water comes out of this vent then I am going attatch a hose between the vents on the first and second radiator, close the flows on these and open the returns, open flow and return on third radiator. My theory is that if the blockadge is between 1 and 2 then the flow will go through rad 3 and then into the return of rad 2 through the pipe to the 1st rad and then out through it's return. If this is successful then I will try and flush mains water through the return pipe between 1 and 2, no problem flushing in return direction but if I try the other direction I will have to block off the vent and cold feed. If this does not work then I will have to get somebody with power flush equipment to try and clear it as I do not have a power flusher.

Should all my investigations prove that there is a blockage then I think the only option is to run a surface pipe from the return on rad 2 to the return on rad 1 to bypass it, this does not look too difficult.

Anybody got any thoughts on my plans and any other tips would be appreciated. Thanks.

When you come across jobs like this that aren't as straight forward as you would expect, i.e you find a blocked cold feed on changing a 3 port or something like that does everyone tell the customer the price now has to go up?

 

[PlumbBobBob]

i usually say before i start that there may be unforseen problems which will be extra. not had one refuse to pay the extra yet.

 

[dontknowitall]

Best thing is to communicate with the customer. If you are not expecting something and find something to delay you or which will cost much more (for example you just can't turn off stop tap) then stop immediately, explain and give them the choice of you continuing or not.

Remember also, that even if you start a job you're not under obligation to continue. Not good business practice to walk out on a job admittedly, but you have to make a decision for your business to see if it's worth doing the job or not for the money offered.

99% of customers are happy to pay for unforeseen circumstances. Presumably if you take your car in for a service and they tell you that you need new brake discs, as well as pads, and a new battery and shock absorber you'll mutter something to yourself and then tell the garage to get on with the job and pay for the extra when you collect the car? Same goes for this plumbing lark!