Central Heating Pump

[Guest Guy]

Hi All,

 

1 There are 4 pipes leaving the boiler so the HW is gravity fed (this seems to be working fine)

 

2 Everything has been working fine, we noticed things were not so good last weekend but come to think of it, I’ve been getting hot at night for a month or 2.

 

3 Nothing has been tampered with

 

I checked the header tank in the roof and it’s got water in it, I’ve bled the radiators and all are fine. I can’t see any sign of a check valve, just the pump but I’m going to keep looking, there are some wires so I’ll follow them.

 

I get HW in the summer simply by turning the control on the front of the boiler, the motor doesn’t run and all the rads stay cold (well they used to but not now)

 

Yes the rads downstairs heat up as normal when the pump switches on.

 

In the pic below, the upper pipe coming from the boiler splits and goes upstairs to the upper rads and down to the lower rads. The return pipe comes from upstairs and downstairs, joins, goes through the pump and back into the boiler.

 

If all else fails I'll assume that there is a check valve hidden under the floorboards upstairs somewhere so I'll fit a new one in the pipe that goes up into the ceeling.

 

Bill, you knock me out Thanks

[Guest Battery Bill]

Guy

This is ours

[Guest matt11270]

Hi in the summer are you 100% sure you do not get hot water on the rads up stairs if you are there is a zone valve part open on the heating side that is allowing natural convection to the radiators

Matt

[Guest Battery Bill]

And this is the manual switch

 

Olly helped me out a lot last autumn when we had the same problems, this was complicated by a Toss pot local plumber coming round and putting a new pump in upside down :gdit: :gdit:

Anyone in Lincoln area avoid "Curtis Plumbers" they are cr*p

 

Turns out the cause was the return pipe to the radiator header tank had fell down slightly and was sitting under the waterline and causing a vacuum

 

I nearly suggested that to Olly as well

[Guest Guy]

Right, there are definitely no check valves external to the boiler, the only wires exiting it go to the pump and the thermostat in the lounge. If there is a valve then it’s inside the cast iron part of the boiler.

 

I’ll phone Darren for a bit more advice but I think I’m going to have to fit a valve and power it from the pump supply i.e. pump on = valve open.

 

Thanks for all the replies, you lot really are worth your weight in gold

 

All the best

 

Guy

[Big Jim]

Guy, my system is exactly the same as yours, 1970's vintage (somewhat younger than myself never-the-less!) there's no check valves or fancy bits in mine, there's a switch on the timer that is for "just hot water" or "all system" when all it does is actually switches the pump on & off, when the boiler switches on with it just to "hot water only" the radiators upstairs would get warm, the one nearest the vertical feed (bathroom) would get bloody hot, it did this even from the system being installed. what does cure it, is removing the valve on each radiator, and fitting a thermostatic valve similar to the one in the piccy. This also lets you adjust the various rooms to whatever temp you want in each room very easily when you do have the heating on.

 

All these guys have got newer systems with different / better? controls than we have, don't get mislead.

[Longboarder]

Agree with Jim. My system is the same. I even have a Baxi Bermuda back boiler behind the gas fire in the dining room. Can't see the economy in changing it unless I live in this house for another 20 years. I have an air bleed in the pipe going into the hot water tank. If I don't bleed this now and again I get an airlock in the thermosyphon side and the little elves with the jackhammers make a racket and it stops working. I have also turned each of the balance valves on the upstairs rads to closed and then part opened them again so the upstairs flow rate is reduced. This gets the downstairs rads hotter, cools the upstairs ones and makes thermosyphoning through the rads more difficult. A quick suck through the system expansion pipe may help to clear an air lock.

 

Nigel

[Jon Bradbury]

Jim

 

You might find that the radiator in the bathroom is connected to the tank's convector circuit. This is to ensure you can always dry your towels when using the bathroom and is wholly intentional. The idea, of course, is that this is on whenever the boiler is.

 

A quick check of my system indicates this is the case. Oh, and it's probably early 80's.

[Longboarder]

Leave all the valves on that one wide open then.

 

Nigel

[stevedohc2b]

I did not originaly have a check valve but added one with a new 7 day programer. It was not to hard to wire up so that it activated when water was off i have also added thermo rad valve. and 7 more rads to the system. My boiler used to crasn and bang a lot so filled with a non accid clenser as near to the boiler as posable ie the pump connection. Left for a week and flushed and re filled with inhibiter.

if you can build a car this is a a piece of cake.

 

Pm me if you need any help

 

Stephen

[Big Jim]

Jim

 

You might find that the radiator in the bathroom is connected to the tank's convector circuit. This is to ensure you can always dry your towels when using the bathroom and is wholly intentional. The idea, of course, is that this is on whenever the boiler is.

No, my system is not like that, and it's not like the drawing previous.

Basically there's cold water feeds the hot water system just like how it did when it had a boiler behind the fireplace, but now the central heating boiler has 4 pipes coming from it, one pair go just to the hot water cystern as feed & return, and act just like a radiator inside the hot water tank, the other two pipes are the feed and return to all the house radiators, the return side having the water pump in, pushing the water through the boiler.

 

Of the 4 pipes, the 2 pipes that feed either part of the system (1 to hotwater tank, 1 to radiators) come out of the top of the boiler ('cause that's where it's hottest!) and the returns go into the bottom, all into the same water jacket, i think that the water feed for all the heating system is tapped into the return to the boiler from the hot water tank.

the bathroom rad is the first radiator on the system upstairs, and usually traps all the air, needing bleeding approx twice a year.

 

it's been in some 30 years now and still going strong (I shouldn't be saying that! ) so hopefully it'll last a bit longer.

[Guest matt11270]

Do not put thermostatic valves on all the rads allways leave lock sheild valves on the bathroom to stop water hammer when the thermo valves shut down .

Also only fit the thermo valve on the flow side of the rad unless you have got bidirectional valves as this can cause water hammer as the valve closes

 

Matt

[Guest Guy]

Jim, your system sounds exactly the same as mine even down to the bathroom radiator getting the hottest, and is from the same era. If you leave your central heating pump off but your hot water on do your upstairs radiators continue to get hot?

 

If this is the case, what do you do in the summer when it’s warm but you still want hot water?

 

If yours do get hot then it could mean that mine has been broken for the last 2 years (since I’ve been in the house) and has suddenly started working as it should .

[Big Jim]

Guy, that's exactly what used to happen, in summer I used to close the valve on the bathroom rad, the landing rad (next in line) and the main bedroom, as these were the ones that got hot/warm to a greater or lesser degree, but as I said earlier, once I fitted the thermostatic valves to each rad, there's no longer a problem, as the room temp shuts the valve depending on what you've set it at.

 

check out this article.

 

this is the first site that came up after putting "thermostatic radiator valve" into Google. Here

as you can see, you can get them from £10 each.

 

theres even one here for only £6 each.

[Guest Guy]

Right then, I've bought some cleaning stuff and some inhibitor to leave in the system. I'll fit thermostatic radiator valves and see what happens

 

I'm still sure it didn't used to convect round so there must have been some problem that the fairies fixed for me while I wasn't looking.

 

Thanks for all the replies, and I've learned lots about heating systems wich I'm sure will come in handy in the future