I think I have the dreaded blocked cold feed. I have read the FAQs and still have a few q's: i have vented the higher level radiators and no water, well a little dribble then stops. What sort of magnet can i use to detect excatly where the blockage in the pipework is? how comes the hot water tank still heats up as that too is upsatirs on the same level as the cold radiators? thanks..
cold feed questions - have read FAQs
- Thread starter AlexKramer
- Start date
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use any magnet. fridge magnet if you want.
the feed to your cylinder coil is probably lower than the top of your rads.
your pump will useally be next to notice lack of water.
the feed to your cylinder coil is probably lower than the top of your rads.
your pump will useally be next to notice lack of water.
Oh yes i understand now - it us lower in fact and that explains it. Ok i have a fridge magnet, do i put it on the suspected blocked area of the pipe-should there be a strong hold ? what are the signs to look out for ?
run it along the pipe.
useally where the cold feed t's into the system.
you should feel it sticking.
useally where the cold feed t's into the system.
you should feel it sticking.
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it sticks close to where the 15mm pipe comes down and a small section of horizintal 22mm pipe joins it, the 22mm small horizontal section joins another tee piece and 22mm pipe goes up and down from there, i think maybe to the vent and the lower part up from the boiler?? will i need to drain down the system and cut it out? but the system won't drain will it?
Turn off the gate valve in the cold feed.
If the tee that is blocked is quite high, ie above the level of the highest radiator, then chances are that you will not need to drain the system.
If you do you do not need to drain it fully. It will still drain even if the cold feed is blocked, but obviously the exp tank will not drain, hence turning the gate valve off.
If you do not have a gate valve fitted you can bung the cold feed outlet in the bottom of the exp tank.
If the tee that is blocked is quite high, ie above the level of the highest radiator, then chances are that you will not need to drain the system.
If you do you do not need to drain it fully. It will still drain even if the cold feed is blocked, but obviously the exp tank will not drain, hence turning the gate valve off.
If you do not have a gate valve fitted you can bung the cold feed outlet in the bottom of the exp tank.
the system will drain open the rad vent.
bung the pipe in the tank then use a towel when you cut the pipe and you'll only loose whats in the pipe.
bung the pipe in the tank then use a towel when you cut the pipe and you'll only loose whats in the pipe.
I am very greatful to you for your guidance here. Will i need to drain a lot or the whole of the system from the low level drain valve, as when I cut in I don't want a lot of water shooting back up? when I cut the old pipe out and add a new section, i will probably use a compression join is this best?
I am worried when I cut in that the vent pipe will wobble above and move the header tank in the loft above-will this happen, the pipe is clipped above where i am cutting though? also, it is weird that a blocked cold feed pipe, t section, allows the bottom radiators to warm up-as there must have been no circulation for a while, and the pump msut of been working against a dead head?! sorry for all the questions.
I am worried when I cut in that the vent pipe will wobble above and move the header tank in the loft above-will this happen, the pipe is clipped above where i am cutting though? also, it is weird that a blocked cold feed pipe, t section, allows the bottom radiators to warm up-as there must have been no circulation for a while, and the pump msut of been working against a dead head?! sorry for all the questions.
depends where the pipe joins.
you can drain whole system give it a flush out.
compression will be fine.
if you had left it longer the pump would had not got any water over time
you can drain whole system give it a flush out.
compression will be fine.
if you had left it longer the pump would had not got any water over time
Ok thanks, i'll cut in to the affected pipe, use a compression tee and a straight connetor to re-join with fresh pipe.
The cold feed, although was blocked, must have allowed some pumped water from the boiler through though, as the downstairs radiators and hw are OK and must have had some circulation going to them!
The cold feed, although was blocked, must have allowed some pumped water from the boiler through though, as the downstairs radiators and hw are OK and must have had some circulation going to them!
the cold feed from the tank don't have pumped water from the boiler through it.
the cold feed can be full blocked and system still work, its only a means of topping the system up
the cold feed can be full blocked and system still work, its only a means of topping the system up
Where the short horizontal piece of 22mm pipe joins the cold feed, this section has the boiler water going through it. This is where the blockage is.
sorry got ya.
It's ok i get ya too-it must have not been 100% blocked to allow circulation through then??
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