Rads/heating.

nosmo-king

Three rads upstairs only heating at top couple of inches.
Does this mean rads need to be drained/cleaned and if so can I drain one rad at a time and still leave the rest of the house with heat. What is the procedure step by step.
Any info would be greatly appreciated.
Tks n adv folks.

Corkey123

Rads failing to heatup on the top of the rad normally indicates air in the rad that needs bleeding, however the rad heating at the top first can mean a couple of things

As hot water rising to the highest point it could be that your pump is knacked and is failing to circulate the hot water and it is moving to the highest point as hot water will. Do the downstairs rads heatup as normal?

nosmo-king

All other rads in the house including others upstairs heat up fine. For information the three that dont heat up are the ones furthest away from the burner/boiler.
As I said earlier these rads are stone cold below about two inches from top and that bit only gets warm when wall thermostat is above twenty degrees. ..(no stats on rads).
Tks for info

Automan

If the rads have always been like that they might not have been balanced correctly, or there could be a sludge build up in you rads, if so rads will need to be removed from the wall and flushed out using a hose until all the black sludge like water is gone.

JamesM

As Automan says, did this just start happening recently or has it been getting worse for a year or so.
If it has suddenly happened, it could be the water pump - is the pump on full speed ? Could anyone have changed it ? Did you get a new rad in the system recently - anything different that might have caused the problem ?
Turn off all the other rads and see if it makes a difference. If the cold ones heat, then the system might just need balancing.
Jim.

nosmo-king

No, no new rads and the pump has not been touched.
One of the three rads in question has always been poor.
I will try turning off the other rads as suggested..good idea..
Tks all

nosmo-king

Im back...
Turned off all other rads and no change to cold area on all three rads. ( I would say the hot area got hotter).
What do you think is my next move???
Tks n adv

rooferPete

Hi Nosmo,

Have you tried venting the rads, letting the air out of the radiators ?

Should be simple enough, call into a plumbing suppliers or even most hardware shops will have a radiator key.

Make sure the heating is off and vent the radiator by opening the small valve at the top, some are on the back and others are at the end of the radiator (top).

Use a cloth and gently release the valve until you hear air or water starts flowing down the radiator, if neither happens you may need to top up the system.

Presuming you release the air until water flows you will probably have to balance the radiators forcing the water from the rad nearest the boiler / pump to the rads on the end of the line.

It can take a bit of time to get them right but time well spent.

.

Corkey123

As the rad are heating at the top remain cool at the bottom it is now pointing to the pump. It is unlikely to be air as the rads would heatup at the bottom with the air trapped at the top. I would suggest turning off all the rads (upstairs and downstairs) except one of the three in question and see if it heats up as it should. If it does it is possible that the pump is failing to service all the rads up stairs. It it doesn't it is possible the pump has failed completely

You mentioned earlier that one of the rads was alway bad is it, possible that this is the first rad in this sequence of three and that the rads are "daisy chained" i.e one feedng two feeding three. as opposed to be individually fed from the boiler.

Finally check that the system is sufficiently pressurised. If its a close system you should have a gauge somewhere, make the gauge shows at least 1, if its a gravity feed system you will have a small expansion tank in the attic that sure that it is not block in any way and ensure there is a sufficent amount of water in the tank and this provides the pressure in an open system.

Busy weekend eh

JamesM

nosmo-king wrote:

All other rads in the house including others upstairs heat up fine. For information the three that dont heat up are the ones furthest away from the burner/boiler.
As I said earlier these rads are stone cold below about two inches from top and that bit only gets warm when wall thermostat is above twenty degrees. ..(no stats on rads).
Tks for info

This thermostat - is it upstairs by any chance ? If it controls the upstairs rads, the motorised valve may not be opening fully - only letting a small flow through - Just another idea
Is the house 30 years old,or so. If so, could be sludge. As I said before check the speed of the pump. Some just have 1 speed. Others 2 or 3 speeds. Make sure that it is on the fastest.
Jim.

nosmo-king

Tks all for ur ideas and I will check all out. The system is about 10/12 years old.
Yes, busy w/end ahead but hopefully a good one.
Tks


PS. As the connections going into the rads are exactly the same both ends how do I know which end does what ?.

Automan

JamesM wrote:

This thermostat - is it upstairs by any chance ? If it controls the upstairs rads, the motorised valve may not be opening fully - only letting a small flow through - Just another idea
Is the house 30 years old,or so. If so, could be sludge. As I said before check the speed of the pump. Some just have 1 speed. Others 2 or 3 speeds. Make sure that it is on the fastest.
Jim.

I also think it could be a build up of sludge as this sits in the middle of the rad only letting the corners and top of the rad heat up. This happened in a house I was renting a few years ago and I got a plummer mate to come and help sort it out.
He isolated the rads and took them off the wall and brought them out the back where we flushed the sludge out with a hose, you can see it as its coming out, black dirty water keep flushing and emptying the rad till the water is clear.
Then put the rads back on and open the air bleed to let the air out and water back in, then rebalance the system.

nosmo-king

Im back and all the testing done.

I turned off all rads, except one as suggested and there is no difference.

I checked the pump and it has three possible speeds and it is set at # three.

Cheched water level in small tank in attic and that is fine.

The one wall thermostat control is down stairs and has a range up to 30' c.

I think Im at the drain the rads stage. Do I have to drain the whole system or can I close off one rad at a time and leave the rest of the house with heat.

Balancing...How is that done proberly?

Im now looking forward to the next stage.(Could be getting there)
Tks n adv folks

JamesM

nosmo-king wrote:

Tks all for ur ideas and I will check all out. The system is about 10/12 years old.
Yes, busy w/end ahead but hopefully a good one.
Tks


PS. As the connections going into the rads are exactly the same both ends how do I know which end does what ?.

I've just had a look at the earlier posts. Have you checked that both valves are fully open. Is the valve at the opposite end to the one you usually turn on open. You might have to take the cap off and turn it with an adjustable wrench. If both ends are fully open, then it looks like sludge. This is unusual in a system which is only 10 or 12 years old. Are there soldered joints on the pipes. If these systems are not flushed out thoroughly at the beginning, there will be an awful lot of corrosion in the system. The sludge is corroded metal. I have seen holes appearing in the middle of rads :eek:
Sorry for being pessimistic
You can drain each rad, one at a time. I would turn off both valves, loosen the large nut between one of the valves and the rad. Have plenty of old sheets, towels or something like that. Old, because the sludge is filthy and the marks will never come off. Protect floor, carpet etc. When you loosen the nut try to catch most of the water in some kind of shallow basin or dish. Once the water is flowing, loosening the vent will help to control the flow of water into the basin. Once the rad seems fairly empty, loosen the nut at the other end and lift the rad off the brackets. Before taking the rad downstairs, block off the ends - with plastic bags or something like that. As I said before the sludge is very corrosive. Take the rad outside and flush it out. If it is very bad, then it is likely that the pipes also have some sludge as well - that is more difficult to deal with and hopefully you won't have to think about it.
After you have done the last rad, put an inhibitor into the system (I think that "Fernox" is still available) through the expansion tank. If there is dirt in the tank, try cleaning it out without letting it down into the system. When you put the rads back, open the valves and bleed through the vent.
That's all I can think of for now - someone else may have some other ideas.
Jim.

Corkey123

I'd agree with Jim, you're now down to taking off the rads. Jims description was spot on. Can't emphasis enough the toxicty, stainability, of the sludge. Take every precaution possible as you will regret it if you don't. One suggestion is when you happy that all the water has drained from the rad plug each end of the rad to avoid the sludge dripping out. Then remove the rad of the wall and out it the back as quick as possible - that sludge has a mond of its own. Put a garden hose to one end and turn it on to remove the sludge.

Automan

nosmo-king wrote:

Balancing...How is that done proberly?

With the heating off open all the valves all the way on your rads (both valves on the rad) turn your heating system on and keep checking your rads to see which heats up first make note of it, then check to see which heats up next, make note of it, keep doing this till you know what order all the rads heat up in.
Now go to the rad that heats up first, and close the valve that is normally covered (will need spanner) open it a little at a time and leave for a few mins then check the temp of the rad if it is not back to the original temp open the valve a little again, keep repeating till the rad is warm enough. (I had my hands on the two pipes either side of the rad (not for too long as you’ll burn your hand) beside the valves and was comparing the heat in both till they were nearly the same). Then go to the second rad that heated up and repeat the steps till all the rads have been done. Most likely the last rad in the chain will need the valve fully opened.
Some plumbers have temp gauges that they attach to the pipes and once there is a drop of, I think, 5 Deg then they know that rad is ok, but I could not find these Temp gauges anywhere.
It is time consuming but worth it in the end.

nosmo-king

Tks for that Automan, thats very clear. I will keep an eye out for one of these gauges and if I find one will let you know.
Tks again

nosmo-king

Tks for all the info Jim. I have checked and all the "shield" (do u like it) valves are open approx half way.
Tks again

nosmo-king

Tks Martin C for info. This seems to be serious stuff. I will take care.
Tks

JamesM

nosmo-king wrote:

Tks for all the info Jim. I have checked and all the "shield" (do u like it) valves are open approx half way.
Tks again

Actually it is "lockshield valve":D But, you're getting there Open the lockshield valves fully on the rads that are not heating - give it one last try before you get into the mess of taking off the rads. If it comes to it - this site has good directions:
http://www.helpwithdiy.com/plumbing/removing_a_radiator.html

Jim.

nosmo-king

Will do James.
Thank you

nosmo-king

The flu has entered the house so messing with heating at mom not a good idea. I will hold off for a bit.
Rgds.