Oil boiler heating radiators but no hot water

[richardd]

my boiler is heating the rads but not giving me any hot from the cylinder what is the problem . It is a standard gravity feed system with oil boiler and cylinder.

I have to turn emmersion on for hot water.

 

[dontknowitall]

I'd start by checking the zone valve. If you slide the bar across and it heats the hot water then the motor has probably failed.

 

[tamz]

It will be an air lock or lack of water (stuck ballvalve in heater tank or chocked feed)

 

[richardd]

it dosent have zone valves direct hot from cylinder to hot outlets.

 

[richardd]

does the heater tank not just top up the heating. do you not mean the main cold water storage tank that feeds the cylinder

 

[richardd]

It will be an air lock or lack of water (stuck ballvalve in heater tank or chocked feed)

does the heater tank not just top up the heating. do you not mean the main cold water storage tank that feeds the cylinder

 

[tamz]

Typo. I should have written header tank. You will have 2 tanks in the loft or somewhere high up. The smaller one feeds the heating system.
If you only have one large tank in the loft you may have a primatic cylinder.
Check the 2 big heating pipes on the side of the cylinder (hot water tank). If they just go directly into the tank with no other pipes running upwards it will be a primatic and will be an air lock in the pipes between the boiler and the cylinder.
If there are tees on the big pipes with a 15mm pipe teed from the bottom big pipe and a 22mm from the top one running upwards to the loft or where ever, you have a header tank. Check there is water in it and the valve is free. If there is there could be a choke on the feed pipe further down (or a closed valve).
Failing that it will be an air lock. Best get someone to have a look.

 

[richardd]

I'd start by checking the zone valve. If you slide the bar across and it heats the hot water then the motor has probably failed.

it dosent have zone valves direct hot from cylinder to hot outlets

 

[WHPES]

Assuming it's a standard indirect cylinder, if the vent is not at the top of the inlet for the system water at the top of the cylinder, try bleeding it from here.

If it's gravity, there is a possibility that the pipes are blocked with debris.

 

[richardd]

Assuming it's a standard indirect cylinder, if the vent is not at the top of the inlet for the system water at the top of the cylinder, try bleeding it from here.

If it's gravity, there is a possibility that the pipes are blocked with debris.

it is gravity feed with no zone valves could trhe cylinder be starved of water from the cws tank

 

[richardd]

open vented system

 

[tamz]

Wrong system diagram.
Give me 5 minutes and i'll find one like yours

 

[richardd]

Wrong system diagram.
Give me 5 minutes and i'll find one like yours

thats the system i have open vented

 

[tamz]

It is like one of these

 

[ecowarm]

check the small tank (f&e tank) has water in it, if not ball valve may be stuck. move up and down to free,
Eco