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[Taxi_Driver]

My Central heating is about 30yrs old......8 rads, all connected using microbore pipework.
Boiler is 30yrs old too  and i plan to change it next year....

However I think it may need a descaling/desludging, since ive added a digital room stat......ive noticed on cold nights, that the stat is still calling for heat even after the heating has been on after 4hours (stat set on 20c) Ive had double glazing this year and the house has cavity wall insulation with about a foot of loft insulation.......so it carnt be losing that much heat!

All the rads get hot (upstairs not as hot as downstairs)  and all the rads still keep getting hotter even after the heating has been on for hours.

I know the boiler is old.....but I think maybe the water isnt circulating as it should.

Ive turned off the bypass valve (rad in bathroom doesnt have a stat on it and is left fully on all the time) which helped the rads upstairs get hotter.

Pump is set on 2, i could turn it up to 3, but i think that will just put more strain on it.

So my question is, looking at the fernox website, there are quite different products available.
Is it better to tip the descaller  in the header tank or use one of those aerosol type ones direct into a rad?

I noted that Millwall (in TH's thread) left the descaller in for 2 weeks before flushing it.....is this amount of time it should be left in for, for it to work? 

Ta muchly....

[Taxi_Driver]

Seen this...

http://www.tradeplumbing.co.uk/fernox-ds-40-descaler-and-cleanser.html

with this

http://www.tradeplumbing.co.uk/fernox-central-heating-protector-mb1-inhibitor.html

Will this do?? 

Price seems good + £8.95 del for both products

[paul.lovejoy]

you could try sentinel X400 cleaner and X100 inhibitor

http://www.sentinel-solutions.net/product/listing/central-heating/liquids/

available here also stock fernox

http://www.discountedheating.co.uk/shop/acatalog/Sentinel_Inhibitors_Cleaners_Additives.html

[Kevin Wood]

I would check the basics first. Has it been properly balanced? Get a couple of clip-on thermometers, get it all working and open any TRVs so all radiators are flowing and then measure the temperature drop across each radiator. Adjust the flow valves to get about 10 degrees C drop across each radiator. If you can't achieve this you have too little flow through the system.

I would have thought a microbore system would need the pump on maximum speed - if you can put up with the noise, but the temperature drop is key to whether it's flow rate that's the problem.

Failing the above, is the boiler thermostat set high enough?

I'm not sure how effective an additive will be. If a boiler change is on the cards, might be worth waiting for now, and getting it powerflushed when that time comes.

[millwall]

My Central heating is about 30yrs old......8 rads, all connected using microbore pipework.
Boiler is 30yrs old too  and i plan to change it next year....

However I think it may need a descaling/desludging, since ive added a digital room stat......ive noticed on cold nights, that the stat is still calling for heat even after the heating has been on after 4hours (stat set on 20c) Ive had double glazing this year and the house has cavity wall insulation with about a foot of loft insulation.......so it carnt be losing that much heat!

All the rads get hot (upstairs not as hot as downstairs)  and all the rads still keep getting hotter even after the heating has been on for hours.

I know the boiler is old.....but I think maybe the water isnt circulating as it should.

Ive turned off the bypass valve (rad in bathroom doesnt have a stat on it and is left fully on all the time) which helped the rads upstairs get hotter.

Pump is set on 2, i could turn it up to 3, but i think that will just put more strain on it.

So my question is, looking at the fernox website, there are quite different products available.
Is it better to tip the descaller  in the header tank or use one of those aerosol type ones direct into a rad?

I noted that Millwall (in TH's thread) left the descaller in for 2 weeks before flushing it.....is this amount of time it should be left in for, for it to work? 

Ta muchly....

i use X800 Jetflo Ultimate Cleaner  but i also powerflush  which combined gives excellent results

[Taxi_Driver]

I would check the basics first. Has it been properly balanced? Get a couple of clip-on thermometers, get it all working and open any TRVs so all radiators are flowing and then measure the temperature drop across each radiator. Adjust the flow valves to get about 10 degrees C drop across each radiator. If you can't achieve this you have too little flow through the system.

I would have thought a microbore system would need the pump on maximum speed - if you can put up with the noise, but the temperature drop is key to whether it's flow rate that's the problem.

Failing the above, is the boiler thermostat set high enough?

I'm not sure how effective an additive will be. If a boiler change is on the cards, might be worth waiting for now, and getting it powerflushed when that time comes.

Didnt knpw you had to balance each rad 

As said its a 30yo system and afaik its only had a weak attempt to flush it about 5 years ago when the rads upstairs stopped working......then i used an aerosol type flusher and inhibitor injected into a bleed valve of a rad, but i only left the flusher in for about a day, coz the rads upstairs started working again. Other than that its been untouched i think.

Boiler stat is set on 4 out of 6 max

[millwall]

taxi have a read here  http://www.shadlock.co.uk/energy/heat/chbal.htm    will give you something to go on  although your system is old so a chemical and powerflush is the route i would go for a start

[Taxi_Driver]

taxi have a read here  http://www.shadlock.co.uk/energy/heat/chbal.htm    will give you something to go on  although your system is old so a chemical and powerflush is the route i would go for a start

Thankyou all, interesting read Millwall 

[Sir Tigger KC]

Is it true though that power flushing might not be the best idea in an old system? As it's too much pressure and can cause leaks? 

[paul.lovejoy]

Is it true though that power flushing might not be the best idea in an old system? As it's too much pressure and can cause leaks? 

tell me about it think i am suffering with that this morning

hot flush, what am i like

[Sir Tigger KC]

At least you're not getting a back flush Paul!!!! 

[Taxi_Driver]

I would check the basics first. Has it been properly balanced? Get a couple of clip-on thermometers, get it all working and open any TRVs so all radiators are flowing and then measure the temperature drop across each radiator. Adjust the flow valves to get about 10 degrees C drop across each radiator. If you can't achieve this you have too little flow through the system.

I would have thought a microbore system would need the pump on maximum speed - if you can put up with the noise, but the temperature drop is key to whether it's flow rate that's the problem.

Failing the above, is the boiler thermostat set high enough?

I'm not sure how effective an additive will be. If a boiler change is on the cards, might be worth waiting for now, and getting it powerflushed when that time comes.

Just been reading the guide that Millwall posted a link to.....it doesnt rate the clip on thermometers and recommends using a laser one......so i've just reserved one of these....

http://www.maplin.co.uk/infrared-thermometer-with-laser-targeting-223005 

[Taxi_Driver]

Is it true though that power flushing might not be the best idea in an old system? As it's too much pressure and can cause leaks? 

Not sure......

However on some of the descalling compounds i've been looking at, its says dont use this product if the system is prone to leaks.....but you can get products to fix any leaks......but i guess its like adding radweld to leaking car radiator......and some will advise not using it 

[Shackeng]

This link may be helpful, if not, register free with DIYnot.com, and post your questions, a plumber will answer it very quickly. I've used this site for years, and find it very useful.
http://www.diynot.com/forums/viewtopic.php?p=1167325#1167325

HTH

[Taxi_Driver]

This link may be helpful, if not, register free with DIYnot.com, and post your questions, a plumber will answer it very quickly. I've used this site for years, and find it very useful.
http://www.diynot.com/forums/viewtopic.php?p=1167325#1167325

HTH

Thanks for the link......i've been reading through the pages that Millwall posted a link to.....

So my plan is bung in descaller/sludge remover....

While thats working on the system.......build heat reflectors for 5 of my rads (5 rads are attached to outside walls)

After the descaller has done its job and ive fitted the heat reflectors.......then try to balance the rads.....

Job should be jobbed by then........and it will probably be summer again by then