Bathroom radiator almost totally cold

Buford T Justice

Bathroom radiator in a house, typical 3bed semi d from the 70's. Heating system is about 15 years old. Radiator in the bathroom is almost completely cold, only a bit warm at the very top.

I initially thought it was sludge blocking it up, so I took the rad off and flushed it out. When I put it back in and bled it, it's doing the same thing again, cold all over only warm at the top.

One valve is open the whole way and the other is open one and a half turns (as it was before). It's probably one of the furthest radiators away from the boiler.

I don't see how it can be sludge now given that it's been cleaned out, so I'm open to suggestions as to what it could be, or what I could do to help.

Thanks

lawrencesummers

Sidetrack but how easy was it to open and clear out the sludge?

Buford T Justice

https://www.boards.ie/discussion/comment/121471845#Comment_121471845

Easy enough. Closed the two valves, undid the fittings and lifted it outside and hosed it out. Be careful where you do it though, it's black auld shite that comes out of it and it'll linger on the ground and go everywhere. Small rad so easy enough lifted.

Be sure to have clamped the valve before you crack the nut though so as not to turn the valve and potentially bend the pipes.

reap-a-rat

Is it the last rad in the loop? We had issues with our master bedroom and ensuite for ages and tried the same thing as you with the desludging but nothing helped. Heating system from around 2006. I can't remember exactly what happened, I think the whole system stopped heating up and plumber changed the pump. That solved the problem with the rads at the end of the loop - the pump wasn't strong enough to reach those end rads fully in the time the heat would be on for.

Obviously I'm not a plumber but I know that as soon that pump was upgraded the rads were all warm!

Wearb

https://www.boards.ie/discussion/2058326191/bathroom-radiator-almost-totally-cold

If you turn off all or some of the hottest rads, does the bath one heat?

Field east

https://www.boards.ie/discussion/2058326191/bathroom-radiator-almost-totally-cold

I am not a plumber. I assume that it worked ok before so the fact that is the one furthest away from the boiler should not be the reason. Is there a possibility that the ‘gunge’ is still ‘stuck’ in the rad. Also has the boiler’s pumping power weakened and has not the ability to drive sufficient hot water up to that rad. Sounds befalling alright.

Buford T Justice

Turning off all the other radiators and the affected one now gets fully hot. Does that suggest the pump isn't getting the water around?

Wearb

It might mean they need to be balanced. Start by turning of a few of the hottest one's and then back on about ¼ turn. Leave it a while like that to see how it works.

You might need to throttle others back the same or maybe even increase flow though the first ones if not heating enough.

This is a slow process and might take a few days to get right. There will be times when your thermostat is satisfied and you will not observe any results until it calls for heat again.