Emptying cemtral heating tank

[JohnD]

what chemical was it?

It doesn't matter if it's diluted, as long as it all goes in. Then you fill the system so it gets mixed and circulated by the pump, preferably hot.

If yours is a medium-sized house then one bottle will usually be enough. If it is unusually big you may need a second bottle (they are usually sized for a 100 litre system, including the F&E tank and boiler, which mine is. I have ten rads, mostly doubles.

 

[camerart]

what chemical was it?

It doesn't matter if it's diluted, as long as it all goes in. Then you fill the system so it gets mixed and circulated by the pump, preferably hot.

If yours is a medium-sized house then one bottle will usually be enough. If it is unusually big you may need a second bottle (they are usually sized for a 100 litre system, including the F&E tank and boiler, which mine is. I have ten rads, mostly doubles.

When I said diluted, I mean if some went through the system and was thrown away. The chemical was 'home made' by a local plumbers merchant, so no named chemicals.

When I looked in the tank this morning, the chemical was there also a small amount of red sludge, still there from when I emptied it, I was surprised to see it wasn't disolved.

 

[JohnD]

Was the chemical powder, crystals or liquid? Maybe you can use your pump to squirt it down the F&E, excess pressure and water will escape up the vent pipe. There is very little natural movement in and out of the tank, except when filling. There is a bit of expansion movement as the water heats and cools.

If I were you I'd splash out £15 on some Sentinel X400, and use the drain cock first to make room in the system for it to flow down as it refills. A litre will be the right amount for a typical house.

Your made-up stuff might or might not be as good, but I would run it for a while, then drain and rinse, then use the Name Brand stuff.

If they both work, so much the better - it'll get two good cleans.

 

[camerart]

I intend to empty the system again anyway, so that I can fit Thermo valves to each Rad, so I might take your advice and do it again with a known chemical (X400), at the moment the cast iron boiler clatters when heating up, so the cleaner the better.

The chemical was liquid. £10.

 

[JohnD]

if the iron boiler clonks, it may need a Fernox Acid descaler (if it is rust). The acids are quite aggressive, one ate my jacket
View media item 390
if it is limescale, there is a Sentinel chemical, X200 you can add on final fill, with the X100 inhibitor, that over time dissolves it. It is not aggressive and works in a different way, you don't drain it out.

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

If you have a dirty old system, and can afford an extra £100 or so, add a filter such as the Spirotech that will trap circulating debris, including that loosened by the cleaners, and prevent them forming new blockages.

 

[camerart]

if the iron boiler clonks, it may need a Fernox Acid descaler (if it is rust). The acids are quite aggressive, one ate my jacket
View media item 390
if it is limescale, there is a Sentinel chemical, X200 you can add on final fill, with the X100 inhibitor, that over time dissolves it. It is not aggressive and works in a different way, you don't drain it out.

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

If you have a dirty old system, and can afford an extra £100 or so, add a filter such as the Spirotech that will trap circulating debris, including that loosened by the cleaners, and prevent them forming new blockages.

Blimey! Looks like you were fixing the radiator in a lion cage

These chemicals can get expensive can't they. I also bought some inhibitor liquid chemical from the plumbers merchant. I'm getting doubts about it, although I'm sure it would be fine.

I doubt I'll buy the filter, most probably just put up with the clatter, which might not be there after the second clean.

 

[camerart]

I have some X400 on it's way.

This morning the heating was hot, but the water wasn't. I presume it is the same pipework blocked. Is there a two way valve in this system?, I can't see it. Does anyone know where it might be. It is a back boiler, and pipework boxed in the sides of the chimney breast, and perhaps under the floor boards.

Cheers, Camerart.

 

[JohnD]

if you have a back boiler, it is quite likely that you have a gravity feed (convection current through the pipes) to the cylinder, but we need to see photos of the pipes, pump, wiring and controls to be sure. If there is a 3-port valve, then there will be a thermostat strapped to the side of the cylinder to control it, with a flex which eventually leads to the valve. Or you may have a non-electric thermostatic valve on the return pipe of the cylinder, such as a Cyltrol or a Tapstat.

it might be you have air in the pipes, try bleeding the rads. Also see if the cylinder warms up when you turn the CH room stat down.

 

[camerart]

if you have a back boiler, it is quite likely that you have a gravity feed (convection current through the pipes) to the cylinder, but we need to see photos of the pipes, pump, wiring and controls to be sure. If there is a 3-port valve, then there will be a thermostat strapped to the side of the cylinder to control it, with a flex which eventually leads to the valve. Or you may have a non-electric thermostatic valve on the return pipe of the cylinder, such as a Cyltrol or a Tapstat.

it might be you have air in the pipes, try bleeding the rads. Also see if the cylinder warms up when you turn the CH room stat down.

I bled the rads, no affect.

No combination of hot water/heating settings will heat the water, even though the heating always works ok with thermostat and switched correctly.

For water only, I have never heard any noises when just water is switched, apart from the initial boiler cackle, so I . The boiler seems to try then if I'm correct, switches off once the water inside it gets hot, combined with no circulation.

I haven't had chance to check where the pump is or a diverter valve, I'll do it ok tomorrow.

Thanks, Camerart.

 

[camerart]

if you have a back boiler, it is quite likely that you have a gravity feed (convection current through the pipes) to the cylinder, but we need to see photos of the pipes, pump, wiring and controls to be sure. If there is a 3-port valve, then there will be a thermostat strapped to the side of the cylinder to control it, with a flex which eventually leads to the valve. Or you may have a non-electric thermostatic valve on the return pipe of the cylinder, such as a Cyltrol or a Tapstat.

it might be you have air in the pipes, try bleeding the rads. Also see if the cylinder warms up when you turn the CH room stat down.

OK,

The heating comes from one side of boiler, and switched by the pump.

The hot water looks as though it goes directly from the boiler to the tank coil, but I couldn't see any valve or wires.

I could see 2 wires coming from the mains/clock, 1 went to the pump and the other into the boiler. I can only assume there is a solenoid valve on the boiler? to switch the water on.

I emptied some of the water from the flow/return drain , it was almost clean, the filled and bled the system. It all working again.

Got to do it all over again for the x400 and fitting rad thermo valves.

Thanks, Camerart