No hot water, missus beginning to smell

[Macsen]

Hi

I have a problem with a lack of hot water to taps.The central heating however, appears to be working fine.

I have a fully pumped system with a motorised 3 way valve heated by a Potterton profile 30 boiler. The pump is a Myson SD53 3 speed (set on number 3)

In an attempt to solve this issue I have changed the wall mounted controller unit, the 3 way valve and the Honeywell motorised unit, drained the system, flushed the rads, refilled with inhibitor and bled but still no hot water to taps or shower.

The boiler fires up and remains lit while the C/H is on but when switched to HW only, the boiler fires and switches off after about 15 mins. The pipes leading to and from the pump get as hot as the pump does ( too hot too touch almost) but the hot water doesn't reach the taps.

I figured maybe the pump is stuffed but then would the CH work if the pump has had it? I have undone the hex screw in the centre of the pump as water trickles out and am able to turn the pump a number of degrees by hand so i don't think it is stuck or seized.

I'm running out of ideas guys and er indoors won't let me hose her down in the garden. If i don't get it sorted soon i'll have to run her through a sheep dip or something.

any ideas?

cheers

 

[JohnD]

...lack of hot water to taps...no hot water to taps or shower...the hot water doesn't reach the taps...

do you mean that no water comes out of the taps, or do you mean that water comes out but it is cold?

Is your cylinder hot or cold?

do the radiators go hot when you turn on CH?

what sort of sediment did you get out?

 

[Macsen]

Hi John

There is water to the hot taps, normal pressure etc but it is cold

The sediment from the rads was black in general and thick in one rad in particular.

Radiators hot up nicely when central heating on

The cylinder is foam covered and difficult to access to tell if its heating up but i haven't felt heat there with any certainty. The 22 mm pipe from the vertical joint on the three way valve goes into the cylinder and that pipe is properly hot ( if that helps)

thanks for the reply

 

[bellairaphon]

hi mate quick check, select hw only on your programmer then when your boiler fires check the 22mm pipe that is entering your cylinder mid-way up.. if it dosen't get hot through water passing then it will be your zone valve that will be faulty.

 

[Worldbuilder]

Hi Macsen, if you say that the central heating side works fine, and that the flow to the cylinder is hot but the cylinder is still cold, check the return from the cylinder back to the boiler. If the heating works fine then there is probably either an air lock, blockage or maybe a closed index valve ( gate valve balancing the h/w circuit on the return...if fitted ). If it's air, you could try partially draining the system again and re-filling. Try running a magnet along the pipework on the return of the cylinder if you suspect a blockage. Given that you said a lot of magnetite was in the water, you could try using a de-sludger to remove the blockage - or just cut it out.

 

[TicklyT]

...... am able to turn the pump a number of degrees by hand so i don't think it is stuck or seized.......

You should be able to spin the pump rotor around, not just turn it a few degrees.

 

[JohnD]

the radiators are getting hot, so it seems to my amateur eye that the boiler and pump are OK, but primary circ is not going through cylinder; might be 3-port; might be blockage; might be cyl stat; might be a closed valve, might even be a wiring error.

I don't understand how to manually override a 3-port but someone will.

As the primary flow to cyl is hot there is presumably at least a bit of flow through the coil.

 

[bellairaphon]

as ya man said there look at your valve if you have a 3 port it will have auto - man i.e manual and a little lever switch it with your hand to manual then look it off you'll see how

 

[gas4you]

If there is a blockage on the cylinder return, it usually will be where the return tees into another pipe.

 

[Macsen]

Thanks for the replies lads

i'm trying to upload a picture of the set up in the A/C with indications of which pipes are hot or cold. Not sure if it will help but hey ho

If the return from the cylinder is the pipe from the lowest connection to the cylinder then it is cold. It disappears into the bulk head just after exiting the cylinder so there's not much room to work with that in terms of blockages. If that's not the return from the cylinder i'd appreciate someone pointing out which one is.

The three way valve is new and appears to be working via selection from the controller.

Given what's been said, i'm inclined to think that there may be a blockage someplace. The system was shut down for the best part of two years and upon firing it back up, problems began.

AC

• Macsen
• 25 Jun 2008
• 1

 

[Macsen]

Well i've had a result of sorts.

After removing the motorised actuator from the valve, i noticed that regardless of the demand from the controller, the actuator moved to the heating setting so i moved the valve manually, closing off the heating and lo and behold..... hot water flows in abundance!

Given that the actuator, Drayton, is brand new out of the box, i figure there must be a wiring error although when i replaced it, i put the wires back like for like. The wiring for the wall mounted controller may be the issue though because i was given a wiring diagram for it by the chap who sold it to me and i'm not so sure that he was very assertive in his description of what goes where.

Either way at least there's hot water now but i need to figure out what has to be done to get the system working off the controller as it should. Maybe if i post a few pics of the wiring set up on here, someone may be able to offer some insight?

Thanks to all that offered ideas to date