central heating problems: water temperature & radiator temperature

Dilisk · 25-07-2016 07:27PM #1

Having recently acquired a house, I have been getting acquainted with its
central-heating system, which is oil-fired. I've discovered two problems.

The first problem is that the water from the hot-water taps isn't hot
enough. The second problem is with the radiators: one of them barely heats
up at all, and for certain other radiators, I have various degrees of doubt,
varying with the radiator, as to whether they get hot enough.

The first problem is illustrated when I shave: when washing my face, I like
to have the water as hot as I can bear, but the temperature I get is not
even close to that level.

I'll describe as much of my setup as seems relevant.

The house has two floors.

The boiler, which is not a combi boiler, is outdoors, adjacent to the rear
of the house. It's a Firebird kerosene boiler, manufactured in August 2006.
I don't know when it was last serviced, but I would say it was a long time
ago, if ever.

The hot-water tank is in the hot press, on the upper floor. This tank has
an electric immersion heater, which does make the water more or less as
hot as I want it.

The problematic radiators are all on the upper floor. The worst radiator,
the one that barely heats up, is the farthest radiator from the boiler.
Perhaps that's significant.

When I feel the problematic radiators, I find them all to be warmer at the
top than at the bottom.

I think there may be sludge in the system. I believe this because,
when I bled the radiators recently, some of them squirted dirty, black
water. Also, a small water tank in the attic (I believe it's called the
feed and expansion tank) appears to have at least a little sludge-like
matter inside it.

I expect I'll have to call a plumber; but before I do so, I'd like to have
some idea of what's wrong, and what other specialists I might have to call
in, so I'm hoping that boards.ie can help me with that.

RJF · 25-07-2016 07:45PM

Check the copper cylinder for thermostat. Should be set at 65.
Check for balancing gate valve on coil pipe. May need to be adjusted.
Check condition and age of circulation pump.
Whole system probably needs to be balanced.

K.Flyer · 25-07-2016 07:47PM

You may have a number of issues.
From your description it would appear that you have a neglected system which is in need of a bit of sorting out.
If you have evidence of sludge in the feed / expansion tank, it would indicate pitching is occuring, cycling the heating water in the heating system through the tank, indicating poor circulation / not balanced.
Sludge kills the efficiency of the heating system and who knows how well maintained the boiler is.
You need someone who can cover all bases, power flush the system completely clean, adjust and balance the system, give the boiler a good service and advise on how the system may be improved and correctly maintained.

Wearb · 25-07-2016 07:47PM

In a "new" house you should certainly have the boiler serviced and the plumbing given the once over. Plumber will then tell you what its like and explain the controls.
It could be a lot of things from balancing valve to clogged up boiler to failing pump to sludge etc.

Wearb · 25-07-2016 07:49PM

I need to learn to type faster :pac::pac::pac::pac:

Dilisk · 25-07-2016 08:01PM

RJF wrote: »

Check the copper cylinder for thermostat.

I looked around and about the cylinder for a thermostat, but
couldn't find one.

RJF · 25-07-2016 08:29PM

What type of timer is on your heating system.
Pics of hot press, timer and boiler thermostat would be good.
I'm guessing you have an open system - small tank in attic for heating and large for storage.

Dilisk · 26-07-2016 08:40AM

RJF wrote: »

What type of timer is on your heating system.

A Siemens RWB7.

RJF wrote: »

Pics of hot press, timer and boiler thermostat would be good.

I'm attaching photos of the first two. As regards the boiler thermostat: if I have one,
I don't know where it is.

RJF wrote: »

I'm guessing you have an open system - small tank in attic for heating and large for storage.

I believe I have the type of system described in
www.cfplumbing.co.uk/what-is-an-open-vented-central-heating-system.htm,
which uses the term "open vented central heating system".
I have a fairly large, sealed tank in my attic; on top of it is a
smaller tank, which I believe is called the "feed and expansion tank".

The smaller tank, though covered, is not sealed. It has a ballcock
inside it, similar to what one finds in toilet cisterns.

I'm attaching a photo of these 2 tanks.

RJF · 26-07-2016 09:25AM

Looks like there are no controls on the system. You have a single channel time clock. I now presume there are no wall stats anywhere or second time clock?

When you turn on the heating you are heating everything - upstairs, downstairs and hot water. Bit surprising as looks a new enough system - I was expecting an old system from your description. When was it installed? The original system - rads and pipes. The boiler was 2006 - original one?

Is there a stove, back boiler or solar on the system as it looks as if that is a dual cylinder with 1" pipe on the RHS. Possibly a stove was installed and the cylinder replaced. When?

Where is the circulating pump on the system? The location is important especially on open system.
The boiler stat is a grey (usually) 3x3 inch box on the boiler.

Dilisk · 26-07-2016 10:24AM

RJF wrote: »

I now presume there are no wall stats anywhere or second time clock?

Yes, that's correct.

RJF wrote: »

When you turn on the heating you are heating everything - upstairs, downstairs and hot water.

Yes, that's correct.

RJF wrote: »

When was it installed? The original system - rads and pipes.

I don't know, unfortunately.

Most of the radiators have thermostatic valves, but some have older,
"non-thermostatic" valves, so I suspect the radiators were not all
installed at the same time.

RJF wrote: »

The boiler was 2006 - original one?

The boiler was manufactured in 2006. I know this because I sent
the serial number to the manufacturer and asked them for the date
of manufacture. I don't know whether it was brand new or second-hand
when installed in my house.

RJF wrote: »

Is there a stove, back boiler or solar on the system as it looks as if that is a dual cylinder with 1" pipe on the RHS. Possibly a stove was installed and the cylinder replaced. When?

There is indeed a solid-fuel stove. I have never used it, and have no intention
of using it, but my understanding is that it heats the cylinder and radiators.

I don't know when the stove was installed, but would be willing to bet it
was in or close to 2006. I don't know whether the cylinder was replaced
at the same time.

Perhaps I should say that I am not in touch with the previous owner, so
I can't easily learn about the history of the house.

RJF wrote: »

Where is the circulating pump on the system?

I don't know. I can't see it anywhere, not even in the attic.

I'm nearly sure I've heard the pump when I've been in the bathroom (which
is upstairs), so that may give some sort of a pointer.

RJF wrote: »

The boiler stat is a grey (usually) 3x3 inch box on the boiler.

I believe I've identified it; the attached image contains a photo.

RJF · 26-07-2016 10:42AM

The circulation pump is probably at the back of the boiler. There is an access panel like on the front.
Need to determine if it is on the flow or return pipe - photo if you can. May be tricky to open back panel.
Get back if any problem.

The fact that there is a stove connected to the system, to the rads AND 2nd coil of cylinder, complicates things. Is there circ. pump associated with it? Photos of stove and any associated pipework.

Thermostat on boiler can be higher but leave for now. Need to sort other problems first.

Also another photo of small attic tank and vent pipes going to it, i.e. from higher perspective, would help.

Wearb · 26-07-2016 11:56AM

RJF wrote: »

The circulation pump is probably at the back of the boiler. There is an access panel like on the front.
Need to determine if it is on the flow or return pipe - photo if you can. May be tricky to open back panel.
Get back if any problem.

The fact that there is a stove connected to the system, to the rads AND 2nd coil of cylinder, complicates things. Is there circ. pump associated with it? Photos of stove and any associated pipework.

Thermostat on boiler can be higher but leave for now. Need to sort other problems first.

Also another photo of small attic tank and vent pipes going to it, i.e. from higher perspective, would help.

As RJF said. The setting on the boiler stat isn't the cause of your problems.
I would be surprised if problem can be diagnosed without eyes on the system.

RJF · 26-07-2016 12:33PM

Wearb wrote: »

I would be surprised if problem can be diagnosed without eyes on the system.

Thanks Wearb, I would tend to agree.

However I think we can figure the pertinent questions for the OP to ask once we have a full picture of the system components.

For example the original posts never mentioned a stove or dual cylinder in the system.

Also looking for any safety issues.

Wearb · 26-07-2016 12:58PM

RJF wrote: »

Thanks Wearb, I would tend to agree.

However I think we can figure the pertinent questions for the OP to ask once we have a full picture of the system components.

For example the original posts never mentioned a stove or dual cylinder in the system.

Also looking for any safety issues.

As for safety; can't see any vent on second coil. Only using phone, so could have missed it, or if course it could be elsewhere.

RJF · 26-07-2016 01:42PM

I think the 1" goes to the back right of hot press and then up to attic.
This is why I asked the OP for 2nd pic of small tank - to see if there are 2 vents.

Dilisk · 27-07-2016 04:30PM

RJF wrote: »

However I think we can figure the pertinent questions for the OP to ask once we have a full picture of the system components.

Many thanks, RJF, for taking such an interest in my problem. However, it
seems to me that my time will be used most efficiently if I get a plumber
to visit the house, so I have got in contact with one.

RJF · 27-07-2016 08:43PM

I agree, definitely the best way to go. Let us know how it turns out.

Dilisk · 28-07-2016 07:45AM

RJF wrote: »

Let us know how it turns out.

Will do.

Dilisk · 13-08-2016 01:43PM

RJF wrote: »

Let us know how it turns out.

> Let us know how it turns out.

I don't have the final resolution, and may not have it for some time, so I
thought I should make an interim report.

I got in contact with a plumbing firm. They paid a visit on the 28th.

They removed some insulation which was blocking the ventilation of the
boiler. They also turned up the boiler thermostat somewhat.

They turned on just the upstairs radiators. After a time, the problem
radiators were all heating much better than before. When I asked why this
had happened, I was told that concentrating the boiler's efforts on the
upstairs radiators had probably blasted a blockage out of the way (or that's
what I understood anyway).

They also fixed the problem of the water from the cylinder not being warm
enough. The decisive change here was probably that they opened up a certain
valve (which they called a choke valve) near the cylinder.

They said they would visit again to do some more work, not specifying a
time. What they will do is:

* service the boiler;

* balance the radiators;

* drain the water from the radiators, put a special substance circulating
in the system to clean out the sludge, and come back a week later to
replace this substance with water.

They remarked that the boiler was somewhat underpowered for the number of
radiators in the house.

It may be of interest to you, RJF, that the heated water from the boiler
goes to the solid-fuel stove first, before going to the cylinder.

central heating problems: water temperature & radiator temperature

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