Hot water from boiler not reaching pump

[Doallyn]

So i've just installed a new pump and cylinder - we've turned it all on but the hot water isn't getting from the boiler to the pump, we just get a swishing noise in the pump but no hot pipes. Hot pipes come out of the boiler but it seems its going no where and the boiler has to shut off

everything has been bled but no joy - any ideas?!?!

 

[Softus]

Is this a replacement pump and cylinder, or new installation?

If the latter then either you've piped it incorrectly or you haven't provided enough vents.

Have you vented air from the pump bleed screw?

Do you have a photo of the installation? Hint: "no" is not a good answer.

 

[Rich_Mortimer]

Evening!

Most problems can be found with a little more diagnosis...
These questions are asked as a double check so don't take offence if they seem simple or obvious.

1. when the flow pipe from the boiler gets hot, does it get hot on just one side of the pump or not at all? There shouldn't be any form of valve inbetween the two except the one connected to the pump for isolation purposes.
2. If it does reach this valve, is the valve open? along with the valve on the opposite side of the pump?
3. the next ones obvious, but it's friday after all... is the pump flowing the correct direction? There will be an arrow stamped into the bottom of the casing.
4. was the pump bled also? they don't normally whirr to loud when full of water.

If all of these are ok, and you're still not getting hot water, the only other thing I can think of is to check the hot water is not venting straight into the F&E from the boiler pump?

Hope some of it helps,
Cheers.

 

[Doallyn]

will get a photo!

the pump was replaced the same was as the old one was taken out in the same direction - it feeds from the floor going up into the 3 port valve which feeds the CH and the cylinder coil

the motor has been bled from the screw and i can see the bit inside turning round, the radiators have been bled, and the air valve next to the pump bled - but no hot pipes around the pump

it would make sense that the pump is the wrong way round but i'm sure its not as it was a straight replacement!

 

[Doallyn]

Evening!

Most problems can be found with a little more diagnosis...
These questions are asked as a double check so don't take offence if they seem simple or obvious.

1. when the flow pipe from the boiler gets hot, does it get hot on just one side of the pump or not at all? There shouldn't be any form of valve inbetween the two except the one connected to the pump for isolation purposes.
2. If it does reach this valve, is the valve open? along with the valve on the opposite side of the pump?
3. the next ones obvious, but it's friday after all... is the pump flowing the correct direction? There will be an arrow stamped into the bottom of the casing.
4. was the pump bled also? they don't normally whirr to loud when full of water.

If all of these are ok, and you're still not getting hot water, the only other thing I can think of is to check the hot water is not venting straight into the F&E from the boiler pump?

Hope some of it helps,
Cheers.

When the boiler is on downstairs only the pipe coming out of the boiler gets hot - nothing upstairs where the pump and cylinder are gets hot at all - its as if there is no water actually circulating !? i can't see under the floor boards to map out exactly whats going on - we've only moved in 6 months ago

 

[Doallyn]

and yes both valves either side of the pump are open

 

[Doallyn]

picture!

 

[Softus]

1. There shouldn't be a gate valve on the cold feed.

2. The cylinder stat isn't sitting right back against the copper wall of the cylinder, and isn't retained by a strap or elastic cord.

3. Do you get any water coming out of the F&E vent?

4. Did you (and do you still) get water from the pump bleed screw?

5. What speed setting is the pump on?

6. WTF is that exposed connector block doing there?

7. Does the flow pipe from the boiler rise all the way to the pump?

 

[Doallyn]

1. No idea on that - thats what was there when we got here

2. Cylinder stat is still to be activated - thats another story its just the CH at the moment thats running

3. Haven't checked - i assume by F&E you mean the overflow in the loft on the CH tank will take a look

4. Still get water from the bleed screw

5. Pump is on 2 i've tried it on 3 aswell just speeds up the swishing noise

6. That block is being wired in still (see 2) caution is being taken!! You should of see it before!

 

[Doallyn]

7. Does the flow pipe from the boiler rise all the way to the pump?

Not sure what you mean by this one

 

[Softus]

Does it ever become horizontal, or, horror of horrors, run downhill?

 

[Rich_Mortimer]

Have you manually checked the 3way? The pump could be fine...
If the valves shut the water won't pass the pump and won't heat up! Use the little lever on the valve to open it manually. Did the valve get unwired during the process?

 

[Softus]

1. No idea on that - thats what was there when we got here

It's a potentially bad thing to have, because someone might shut it.

2. Cylinder stat is still to be activated - thats another story its just the CH at the moment thats running

I'm losing it here - why have you got a 3-port valve with an inoperative cylinder stat?

3. Haven't checked - i assume by F&E you mean the overflow in the loft on the CH tank will take a look

No, not the overflow - that deals with overflowing. By F&E I mean the feed and expansion cistern that provides a head of water to the heating circuit.

4. Still get water from the bleed screw

OK. So what position is the motorised valve in?

5. Pump is on 2 i've tried it on 3 aswell just speeds up the swishing noise

That would be consistent with:

a) closed (or broken) pump isolating valve;
b) closed 3-port valve
c) a blockage
d) an air lock somewhere below the pump

6. That block is being wired in still (see 2) caution is being taken!! You should of see it before!

Why are you testing the system in such a half-ars*d state?

 

[Doallyn]

The 3 port got changed as part of the refit - it appears to be operating correctly it moves to the right place when the CH comes on!

Nothing is happening in the tank upstairs - its very quiet and still when the pump is running no water in and its full?

The whole electrics thing is odd - when wired up as per instructions i get a current from the HW OFF and the HW ON from teh programmer!?? they are wired correctly 1 & 3 but i get a current from both which blows the fuse when the cylinder stat is wired in - so its off at the moment and i'm just trying to get the CH working as its so cold

 

[Rich_Mortimer]

I don't blame you for wanting to get warmed up!

There will be two tanks in the loft. The big one is your bath/shower water, then the smaller one (F&E) tops the heating up when in sue. that should be an inch or so over the level of the cold feed pipe coming from the bottom. is the valve staying open? try locking it into the filling/draining position using that manual switch. also, have you definatly still got water going into the boiler? if the F&E is empty you need to get water into it to allow the system to run correctly