No Hot Water - Gravity Fed System

[Monkey Wrench]

I think he means even more scary - using the boiler!

Hmm, I think I'd need a pair of the The Wrong Trousers to try that one ;-)

 

[Monkey Wrench]

If I find that the cylinder flow/return pipes are blocked with magnetite, whats the best way of breaking it down and clearing it ?

Thank you.

 

[Monkey Wrench]

Pull stats and boil it.

I'm certainly not brave enough to try this, particularly as it seems you mean bypassing all stats (boiler included). However, I'm curious to know that, as there's no flow/return from the boiler to the cylinder (and hence no water), how boiling would cure the issue ?

Thank you.

 

[joni os]

Go with Best. Get your magnet out. Cut out and replace effected area.

 

[Monkey Wrench]

Thanks for that Joni so.

I just hope the blockage isn't in the cylinder coil itself !

 

[Monkey Wrench]

Ok, so I went back last Monday and, before checking pipework with a magnet, turned the hot water and heating on. As previously stated, the hot water cylinder is in the loft and the flow/return pipe run from the Rayburn in the kitchen to the cylinder in the loft (via pump & diverter valves under first floor hall) is about 30-35 feet. After turning the hot water/heating on, I went straight up to the loft to check the cylinder (took a couple of minutes at most) and the flow pipe to the cylinder was already getting warm and after another minute was hot. However, after a few further minutes, the return pipe hadn't warmed up at all.

I then part drained the system, disconnected the flow/return from the cylinder and ran some water through the cylinder (not mains pressure but using a bottle of water) and, apart from a bit of discoloured water coming out the other end, found the cylinder coil to be clear.

I've checked 50% of the flow/return pipework to the cylinder with a magnet (the other 50% is in a difficult to access loft/ceiling void) and it's clear.

Surely, if there was a blockage, there's no way the flow pipe at the cylnder would have warmed up so quickly (if at all) as there's no where for the water to go !

 

[Best]

Ok, so I went back last Monday and, before checking pipework with a magnet, turned the hot water and heating on. As previously stated, the hot water cylinder is in the loft and the flow/return pipe run from the Rayburn in the kitchen to the cylinder in the loft (via pump & diverter valves under first floor hall) is about 30-35 feet. After turning the hot water/heating on, I went straight up to the loft to check the cylinder (took a couple of minutes at most) and the flow pipe to the cylinder was already getting warm and after another minute was hot. However, after a few further minutes, the return pipe hadn't warmed up at all.

I then part drained the system, disconnected the flow/return from the cylinder and ran some water through the cylinder (not mains pressure but using a bottle of water) and, apart from a bit of discoloured water coming out the other end, found the cylinder coil to be clear.

I've checked 50% of the flow/return pipework to the cylinder with a magnet (the other 50% is in a difficult to access loft/ceiling void) and it's clear.

Surely, if there was a blockage, there's no way the flow pipe at the cylnder would have warmed up so quickly (if at all) as there's no where for the water to go !

Yes, the flow pipe can heat up fairly quickly as it is only the water in the pipe heating up. It may only be passing through it very little due to a blockage or air lock. I see this very often on a cylinder with return pipe nearly blocked totally. Something strong, but flexible pushed down into pipe would be handy.

 

[SimonG]

Airlock.

 

[kris]

Ok, so I went back last Monday and, before checking pipework with a magnet, turned the hot water and heating on. As previously stated, the hot water cylinder is in the loft and the flow/return pipe run from the Rayburn in the kitchen to the cylinder in the loft (via pump & diverter valves under first floor hall) is about 30-35 feet. After turning the hot water/heating on, I went straight up to the loft to check the cylinder (took a couple of minutes at most) and the flow pipe to the cylinder was already getting warm and after another minute was hot. However, after a few further minutes, the return pipe hadn't warmed up at all.

I then part drained the system, disconnected the flow/return from the cylinder and ran some water through the cylinder (not mains pressure but using a bottle of water) and, apart from a bit of discoloured water coming out the other end, found the cylinder coil to be clear.

I've checked 50% of the flow/return pipework to the cylinder with a magnet (the other 50% is in a difficult to access loft/ceiling void) and it's clear.

Surely, if there was a blockage, there's no way the flow pipe at the cylnder would have warmed up so quickly (if at all) as there's no where for the water to go !

When u emptied the system did u manually open the zone valves to allow proper filling of the system , ?

 

[Monkey Wrench]

Thanks again for the responses.

Yes, the flow pipe can heat up fairly quickly as it is only the water in the pipe heating up. It may only be passing through it very little due to a blockage or air lock. I see this very often on a cylinder with return pipe nearly blocked totally. Something strong, but flexible pushed down into pipe would be handy.

Ok thank you, certainly worth a try with a sturdy piece of flexible hose pipe.

Airlock.

Thank you, but I've loosened both the flow and return connections at the cylinder and there's water at both. There's also an auto air vent on the cylinder flow pipe so surely any airlock would have vented out through that by now !

When u emptied the system did u manually open the zone valves to allow proper filling of the system , ?

Thank you, yes, I manually opened both zone valves.