My boiler

[ryetee]

Can someone tell me why my boiler has an intermittent problem with the hot water. It did it last weekend - I had a look at it did nothing besides take the front off and havd a look and it's worked since then. The boiler itself has a themostat on it - I'm not sure if this is redeundant or whether it used to be for the central heating or what. There seems to be a copper wire (no insulation) coming from the area of the thermostat dial which dispappears into a hole 3/4 of the way up boiler.

I've got a gravity fed system with no thermostat on or near the hot water tank. There's no pump outside of the CH pump. No motorised valves (whatever they are).

So what controls the hot water. The thermostat? What's the copper wire for? HELP I'm going mad.

 

[ryetee]

actually the 1st post may be a re3d herring
i have 4 pipes that go into the hot water tank
1 in the middle which is red hot when the boiler is on
2 at the bottom on opposite side - one is cold and the other gets hot when the boiler is on but not hot enough that you can't hold it
the pipe at the top which used to get hot whenthe thing worked remains cold to luke warm
any ideas?
the hot pipe at the bottom should i guess be luke warm as it's returning cold water to the boiler - yeah?

 

[masona]

This is the boiler thermostat which control the flow return water temperature.What number is it set at?

Trying to understand your system,do you have a have a cylinder? a expansion tank ? (small tank) as well as a water tank?

 

[ryetee]

I've had the thermostat set at all levels.
I have a hot water cylinder described in my othe rpost with the 4 pipes going in (out) of it. I belive I have an expansion tank as there is more than 1 water tank in the loft

 

[masona]

Could be number of things your boiler thermostat could be playing up or faulty with built-up of dusts.Carefully take it apart and blow the dusts out.When you done that set it at between 3 to 4,and do this test,switch the boiler on for approx 10 mins then turn the boiler thermostat down to zero.It should shutdown.You should also have a cylinder thermostat 1/3 from the bottom of the cylinder,have a look at that as well.Your boiler might need a service with new thermo-coupling etc.Without looking at the job,not easy to rectify the problems on the forum..........

 

[ryetee]

Thermostat works - I can here it clicking on and off. Haven't got a thermostat on the cylinder.
Could I have air in the system as I said in my second post the pipe into the middle of the cylinder get s red hot when boiler is on. the pipe below starts to warm us as if all the hot water is draining away. the pipe at the top which used to get red hot gets luke warm.

 

[masona]

Are you getting a good flow rate out of your hot taps?,if so you wouldn't have an airlock.What is the hot water temperature like?

When you say the pipe in the middle of the cylinder get red hot,is this the pipe on top of your cylinder which goes straight up to the water tank or on the side with inlet and outlet which is connected to the coil inside the cylinder which heat the water up?

Do you have radiators?

Your water cylinder should have thermostat which control the water temperture unless it is control by the boiler thermostat

 

[ryetee]

masona
think i may have solved this or at least partially
the header tank was almost empty and the ballcock was sezied - i've freed the ballcock up and have filled the tank up and have seen an improvement straight away

just to answer your questions though - the flow rate is ok - upstairs is better than downstairs though

the pipe that gets red hot is on the side

yes i have radiators

must be controlled by bioler thermostat.

One further question why dows the bathroom radiatior heat up when hot water is on - is this because the pipe flows through that and would this bve a way to bleed air out of the system?

thanks in anticipation!!!

 

[masona]

When the hot water is on,your return flow is using the same line as the radiator back to the boiler and your bathroom radiator is the nearest one to it which the heat transfer backward to your radiator.Some system have a gate valve to reduce the heat back or you can turn down the return valve on the radiator.Also it is known to have bathroom radiator link up to the hot water system.

 

[MANDATE]

Can I just throw in a couple of points.
Not all systems have a cylinder stat,the temperture in the cylinder being controlled by the boiler stat,it is the same water being cirulated so the hotter the boiler water the hotter the cylinder water.
When a complete heating is installed it is usual practice to place the bathroom radiator on the hot water side of the system which is ideal in summer.
I'm surprised your flow rate is better upstairs, the pressure of the hot water is created by the 'head' of water ,which is the distance from tap to water in tank,upstairs giving a poorer flow.If you have a hand shower on your bath taps turn on the hot and raise the shower head and flow will almost stop

 

[ryetee]

Thanks to everyone for their helpful comments and suggestions.
Mandate - thanks - the crap flow is in the kitchen but other taps downstairs are good so it's probably a tap thing which i can't be bothered to look into (wife's not complaining so it can't be a problem!)

think i've learned quite a lot here so thanks again