Heater system issues

[hfxrzw]

I have some (quite a few) problems with my DHW/CH system.
The house is from 1979 and was 10 years ago extended.
When I bought the house last August I noted that a valve fitted next to the heater leaked over its stem. When I wanted to overhaul the valve and therefore disconnect it electrically I noted that it was not connected (only the blue wire was connected, brown was loose). Looking in the connection box it was a big mess electrically. I have tried to clean it up a bit, but will need to improve further. I had to make my own schematic as nothing made sense. At that time it was noted that the room thermostat was disconnected and further the timer looked so shabby that I decided to replace it.
Regretfully I can not follow the piping completely and therefore do not exactly know what kind of system it is. I looked on various sites and found some reference to schematics and concluded the system should be a "Fully pumped system with a 2-port valve for optional CH".
Most heaters have TCV's. Therefore I connected the valve in series with the wall stat. There is no Cylinder stat connected to the system. This has the system working, but then I noted further problems as follows:

1) The pump is noisy and vibrates and this seems to increase.
2) It is as if you can hear the water being pumped through the system. Sounds maybe odd, but it makes more noise than I’m used to.
3) One TCV starts to hammer when the set temp is reached.

I don't know if the above could be related or not. Any ideas?

Many thanks, Rene.

 

[gas4you]

1) Could be old knackered pump, no by-pass valve fitted, blockage in pipe work.

2) Could be lack of water in the system, blocked cold feed, or severe air.

3) TRV is uni-directional and has been fitted against the flow.

 

[hfxrzw]

1) Could be old knackered pump, no by-pass valve fitted, blockage in pipe work.

2) Could be lack of water in the system, blocked cold feed, or severe air.

3) TRV is uni-directional and has been fitted against the flow.

Thanks for the quick response!

- Old pump - could be, everything else is in bad shape.
-There is no bypass, but some radiators haven't got a TCV fitted and are open.
- Blockage - again, could be, but all radiators get warm and I have DHW.
- I think there is enough water, but I'll check.
- how do you check your cold feed, just drain some?
- Whole CH system was bled of air. DHW tank not, but understand that does it naturally to the tank in the attick?
TRV is correctly mounted. Assume it holds a spring loaded valve. Can these springs break?

THANKS, Rene.

 

[doitall]

The pump could be fighting a battle.

The MV should turn the boiler and pump on, what controls the hot water.

The radiator valve banging is down to the pressure differential exceeding the manufacturers design, fitting an auto by-pass will cure that.

 

[hfxrzw]

I have added a link to some photo's of the set-up below, hope it works.

The boiler and pump are turned on by the timer switch on the HW contact. The CH only comes on if the HW is on (function of timer switch) and then switches the valve in series with the room stat.

This is an open system (open tanks in the attick) so I don't understand how you can get too high a pressure in the system.

Am I missing something?

 

[doitall]

I have added a link to some photo's of the set-up below, hope it works.

The boiler and pump are turned on by the timer switch on the HW contact. The CH only comes on if the HW is on (function of timer switch) and then switches the valve in series with the room stat.

This is an open system (open tanks in the attick) so I don't understand how you can get too high a pressure in the system.

Am I missing something?

That valve on the flow from the boiler will shut the circulation off through the pump.

The pressure is not system pressure but pump pressure, to prove my point take the head off the trv and the problem will be gone.

 

[hfxrzw]

I did what you suggested. Took the head of and tested operation of the valve (pressing the pin in and out). I could repeat the noise by almost closing the valve (TRV) manually.

 

[JohnD]

provided that radiator gets nice and hot, it is possible you could quieten the TRV by closing down the lockshield valve at the other end. this will reduce flow through the rad. Count the number of turns you make in case you need to return it to previous setting.

the TRV closes by the pin pushing down a sort of piston. If the water pressure pushes on the piston in the same direction, when it is nearly shut, the pressure can push the piston against its seating with a snap. If the TRV was on the other end, the flow would be trying to hold it open, so you would not get this bang.

BTW you have quite an old, open system, so it is probably full of sediment. You can clean this out if you like, at modest cost. If you can afford an extra £100 and do simple plumbing, you can add a Magnaclean as well which will trap loose circulating black sediment indefinitely (this is in addition to a clean, not a substitute). Reducing the sediment will allow you to turn the pump speed down, which will reduce noise. it may possibly also reduce pressure and stop the TRVs banging.

those bare copper pipes would benefit from some Climaflex or other pipe insulation which will reduce heat loss and save energy.

p.s. to check for blocked cold feed, tie up the ball valve in the F&E, note the water level, draw off a bucketful of water from the drain cock downstairs, observe if the water level has dropped by one bucketful; untie the ball valve

 

[hfxrzw]

John, many thanks!! Great info. Indeed I will need to spent some money. I'll clean up the electric wiring and will look at the pump tomorrow. I already got some X100 and X400 on order. Any ideas about that filter and a flow control valve i.c.w. the age of the equipment? I think that I'll have to have it replaced after the winter. Assume that filter will be good anyway i.c.w. the age of the radiators. Cheers, Rene.

 

[JohnD]

I am just a householder, but I can't see a Magnaclean doing any damage. It is not actually a filter, the water swirls through it in a vortex and the black sediment is attracted to and retained by a powerful magnet. As it is not a filter it does not get clogged and impede water flow.

It will hold a very large amount of sludge but once it is fitted you can unscrew the top and empty the sludge off the magnet without any plumbing skills.

 

[JohnD]

here we are http://www.adeysolutions.co.uk/subprofessional.asp?id=246

http://www.youtube.com/watch?v=uDgegChsLvc

sediment is liable to clog and damage the pump or boiler, so it needs to be clean if you replace either.

 

[doitall]

As I said the noise is caused by the pin bouncing when the pump pressure exceeds the manufacturers differential.

A auto by-pass is required, A. to control the pressure, and B to keep the pump lubricated

 

[hfxrzw]

Team, really appreciate the info. With replacement I ment pulling all the **** out and getting a combiboiler installed.

 

[doitall]

That looks like a good idea if you like Combi's

 

[JohnD]

I like cylinders