Radiators not getting hot enough

[Meggalar]

Hi, i'm after some help to this problem:

The radiators in our house aren't getting hot anymore, they do get warm but this isn't enough to warm the house properly. Although the other day I did notice that they did get hot first thing in the morning but then throughout the day they are just warm.
The boiler is an Ideal Classic NF70 with a hot water cylinder upstairs.
The room thermostat clicks on about 16 degrees but the temperature in the room doesn't get above 16 degrees, i've checked.
I've also noticed that the pump (i think) makes a humming noise you can hear through the house the whole time the heating is turned on, is this right?
Any help would be appreciated.
Thanks

 

[LUNAT]

HI

can be many things
1.radiators too small
2.house not insulated properly
3.boiler temp low
4.rads too old /crap in the system
5.gas supply low to the boiler
6.plus more

 

[Ronald0]

If you turn the room stat up do the rads stay on longer?

Is the boiler stat set to max?

 

[moorlandman]

Suppose you have checked all rads for air locks, its worth checking to see if your pump is air locked ( usually a big chrome screw flush with the middle of the pump body) unscrew it a bit and see if you release any air.

Good luck

 

[moorlandman]

Suppose you have checked all rads for air locks, its worth checking to see if your pump is air locked ( usually a big chrome screw flush with the middle of the pump body) unscrew it a bit and see if you release any air.

Good luck

After bleeding any air from the pump, put the blade of a screwdriver onto the pump body (whilst its running) and press your ear against the handle ( like a stethoscope) if the pump sounds very noisy, chances are its knackered. A new pump might solve your problem.
Is the hot tap water getting hot ? if so. it could be that your motorized valve is not working, you can sometimes override the valve motor by sliding a small peg,(which protrudes from the valve case) along its slot till it locks in place.
If you do this, you wont be able to have 'heating off - hot water only' - it will be 'heating and hot water full time'. Of course the boiler should still obey the room stat as far as switching on and off.
I'm speaking from personal experience Good luck.

 

[Meggalar]

Hi,
I've checked the radiators and the Grundfus pump, none of which needed bleeding. No air came out of the pump just a thimble full of water.
The pump is currently on setting 2.
I've also checked the cold water header tank in the loft. The water inside it was luke warm but this was after the heating had been on all morning - I assume thats normal. However I did notice that the level had dropped and there was a water/tide line about 2 inches higher up than the water level on the inside of the tank. I've now allowed more water in it.
I've recently insulated the house loft and cavity wall - so thats not a problem.
The hot water tap doesn't appear to be as hot as it normally is either.
Many thanks for your help so far.

 

[jackthom]

Can you (carefully) feel how hot the CH water is where it leaves the boiler.

If this pipe is getting very hot and then the boiler is shutting down for a while before running for a further short period etc, there is a circulation problem and a likely candidate is the pump.

On the other hand if the water leaving the boiler isn't really hot the problem is more likely within the boiler itself.

 

[Meggalar]

I've just checked the water leaving the boiler when the heating is on and the pipe is really hot. The radiators in comparison just feel warm.
Is it time to call out a heating engineer?
I was hoping avoid it, as I can do without the expense at the moment.
Thanks everyone

 

[moorlandman]

Hi,
I've checked the radiators and the Grundfus pump, none of which needed bleeding. No air came out of the pump just a thimble full of water.
The pump is currently on setting 2.
I've also checked the cold water header tank in the loft. The water inside it was luke warm but this was after the heating had been on all morning - I assume thats normal. However I did notice that the level had dropped and there was a water/tide line about 2 inches higher up than the water level on the inside of the tank. I've now allowed more water in it.
I've recently insulated the house loft and cavity wall - so thats not a problem.
The hot water tap doesn't appear to be as hot as it normally is either.
Many thanks for your help so far.

I'm not a heating engineer but, first of all, which header tank do you mean, the central heating header or the hot water cylinder header ? I don't think the central heating header tank water level should drop so much that you can see a tide mark where the level normally is, the ball cock valve should keep it topped up ( same applies to the hot water header). A Water level drop in the central heating header would indicate to me that there is a leak somewhere, or the ball cock valve aint working correctly.
If the water in the hot water cylinder header is warm, it could indicate that the water in the cylinder is overheating and escaping to the header tank via the expansion pipe (which comes out of the top of the hot water cylinder)
Sounds as though either your pump is on the blink or the motorized valve is stuck, the motorized valve is usually located near the pump it's a silver tin plate box with a pipe in and out, try manually sliding the tab along its slot and lock into the notch at the end of the slot.
Cant think what else to suggest, best of luck

 

[jackthom]

I've just checked the water leaving the boiler when the heating is on and the pipe is really hot. The radiators in comparison just feel warm.
Is it time to call out a heating engineer?
I was hoping avoid it, as I can do without the expense at the moment.
Thanks everyone

Because both the heating and hot water are affected I'd put money on the pump being the culprit, but nothings 100% certain.

It's not a difficult thing to replace, provided you are confident doing a bit of mains electrical wiring. Certainly should be an easy job for an engineer.

 

[Meggalar]

I've found the motorised valve unit, although there appears to be 2 of them. One is on the pipe that comes directly out of the hot water cylinder, the other is next to the pump.
I've altered the one next to the pump and pushed the sliding switch into the notch. This does seem to have made a difference and the radiators are getting starting to get hot, i'll wait and see if it solves it.
Many thanks

 

[moorlandman]

I've found the motorised valve unit, although there appears to be 2 of them. One is on the pipe that comes directly out of the hot water cylinder, the other is next to the pump.
I've altered the one next to the pump and pushed the sliding switch into the notch. This does seem to have made a difference and the radiators are getting starting to get hot, i'll wait and see if it solves it.
Many thanks

Keep everything crossed !!

 

[moorlandman]

I've found the motorised valve unit, although there appears to be 2 of them. One is on the pipe that comes directly out of the hot water cylinder, the other is next to the pump.
I've altered the one next to the pump and pushed the sliding switch into the notch. This does seem to have made a difference and the radiators are getting starting to get hot, i'll wait and see if it solves it.
Many thanks

Keep everything crossed !!

Hi, just out of interest, is the heating working now ?
Cheers

 

[adarsh]

in my house all central heater radiator not heated well, i have set thermoset at miximum more then 25 and running boiler gas boiler 24 hour but all pannel not heated well. however water become too hot and not able to consumable.
i have already bleeded the radiator. there are two big radiatior that are heated on upper side but not on lower side however all the input pipe are too hot.

Please suggest i am worried aobut gas bill because I running boiler full day.

 

[Blagard]

in my house all central heater radiator not heated well, i have set thermoset at miximum more then 25 and running boiler gas boiler 24 hour but all pannel not heated well. however water become too hot and not able to consumable.
i have already bleeded the radiator. there are two big radiatior that are heated on upper side but not on lower side however all the input pipe are too hot.

Please suggest i am worried aobut gas bill because I running boiler full day.

Adarsh, you need to start a new thread with a new topic. That way you should get some help on your problem. Although you have a similar problem I suspect the cause my be different