Hi all, first post,
I'm looking for some advice on upgrading my central heating/hot water system. I moved into my house a few months ago and I’m finding that my gas bill seems very high (using about £200 a month). It’s an old croft house built in the 1800’s so 2ft thick granite stone walls, I’m not sure about the insulation but the house was renovated sometime in the 1990’s I believe so I’m hoping it’s pretty decent. It’s all Upvc double glazed and heat retention doesn’t seem to be too bad so I don’t think I’m losing too much. The rooms are quite large, three bathrooms and three bedrooms so there’s quite a lot of space to heat.
I’ve been investigating the heating/water system and I appear to have a gravity hot water / pumped 2 pipe central heating system. There’s a non-condensing boiler in the utility room and a 7 day programmer timer for HW/CH. When the CH is on at the timer the HW is automatically on too, there is no option to have only CH. The hot water tank is in a cupboard in the upstairs bathroom and the header tanks for the HW and CH are on a shelf in the same cupboard above the tank. The CH feed and return pipes come up through the floor of the cupboard and T into the to the tank coil, the feed then goes up to the top of the header tank presumably to allow for expansion and the return goes up to the same tank and is connected to the bottom, again presumably to feed cold water into the system when water is lost. The tank is filled from the water header tank and the hot water feed to taps comes off the top of the tank. There is no thermostat on the tank, the only thermostats I have is a room stat in the hall downstairs which is also the only area with a radiator which does not have a TRV which I believe is correct, and a dial on the boiler to control the temperature of the water leaving the boiler.
The problems I have found with this system are that:
1. The only way to control the HW temperature is to adjust the one and only dial on the boiler, if I turn it down so that the water is not scalding hot then the radiators can’t achieve a high enough temperature to heat the rooms.
2. Even when the house is up to temperature and the stat is not calling for central heating the boiler regularly kicks in. The hot water tank upstairs is up to temperature because the water is scalding hot and is rarely used since all showers are electric and the dishwasher and washing machine are cold fed only.
3. I think the room stat only controls the CH pump and cannot switch the boiler off then not required.
So after that lengthy explanation I’m looking to find out what my best options are for upgrading the system. I’ve spent all day researching this on the internet and have learned a bit about C, Y and S plans. It seems the simplest solution is to add a 2 way motorised valve between the boiler hot feed pipe T and the tank coil connection and a tank thermostat so that I can control the HW temperature which will shut the valve to this side of the system when the water is up to temperature. But if that truly is the simplest solution is it necessarily the most efficient? I’ll be starting to re-decorate the house at some point and I don’t want to find I should have done more to the system before I decorated. Its solid floor downstairs so I presume the pipes are run behind the plasterboard, they certainly disappear into the plasterboard behind the boiler anyway and I have not found any access anywhere to get at them without probably ripping into the walls. So my other plan is to rip into the walls and change it to an S or Y plan system by T’ing the tank hot feed from the boiler into the CH hot feed after the pump and installing either a three port mixing valve as the T or two port valves on either side of a standard T. Then I presume I would have to divert the return pipe from the tank into the CH return between the boiler and first/last radiator. I have lots of other questions about this like what happens to the CH header tank/pipework in all of this and what additional controls I would need to do all of this. And if I go that far then should I replace the old boiler for a new condensing boiler at the same time?
I’m an offshore heating and ventilation engineer but I work with air duct systems and electric heater batteries so although I think I’m getting my head around this a bit it’s quite different from my day job.
I'm looking for some advice on upgrading my central heating/hot water system. I moved into my house a few months ago and I’m finding that my gas bill seems very high (using about £200 a month). It’s an old croft house built in the 1800’s so 2ft thick granite stone walls, I’m not sure about the insulation but the house was renovated sometime in the 1990’s I believe so I’m hoping it’s pretty decent. It’s all Upvc double glazed and heat retention doesn’t seem to be too bad so I don’t think I’m losing too much. The rooms are quite large, three bathrooms and three bedrooms so there’s quite a lot of space to heat.
I’ve been investigating the heating/water system and I appear to have a gravity hot water / pumped 2 pipe central heating system. There’s a non-condensing boiler in the utility room and a 7 day programmer timer for HW/CH. When the CH is on at the timer the HW is automatically on too, there is no option to have only CH. The hot water tank is in a cupboard in the upstairs bathroom and the header tanks for the HW and CH are on a shelf in the same cupboard above the tank. The CH feed and return pipes come up through the floor of the cupboard and T into the to the tank coil, the feed then goes up to the top of the header tank presumably to allow for expansion and the return goes up to the same tank and is connected to the bottom, again presumably to feed cold water into the system when water is lost. The tank is filled from the water header tank and the hot water feed to taps comes off the top of the tank. There is no thermostat on the tank, the only thermostats I have is a room stat in the hall downstairs which is also the only area with a radiator which does not have a TRV which I believe is correct, and a dial on the boiler to control the temperature of the water leaving the boiler.
The problems I have found with this system are that:
1. The only way to control the HW temperature is to adjust the one and only dial on the boiler, if I turn it down so that the water is not scalding hot then the radiators can’t achieve a high enough temperature to heat the rooms.
2. Even when the house is up to temperature and the stat is not calling for central heating the boiler regularly kicks in. The hot water tank upstairs is up to temperature because the water is scalding hot and is rarely used since all showers are electric and the dishwasher and washing machine are cold fed only.
3. I think the room stat only controls the CH pump and cannot switch the boiler off then not required.
So after that lengthy explanation I’m looking to find out what my best options are for upgrading the system. I’ve spent all day researching this on the internet and have learned a bit about C, Y and S plans. It seems the simplest solution is to add a 2 way motorised valve between the boiler hot feed pipe T and the tank coil connection and a tank thermostat so that I can control the HW temperature which will shut the valve to this side of the system when the water is up to temperature. But if that truly is the simplest solution is it necessarily the most efficient? I’ll be starting to re-decorate the house at some point and I don’t want to find I should have done more to the system before I decorated. Its solid floor downstairs so I presume the pipes are run behind the plasterboard, they certainly disappear into the plasterboard behind the boiler anyway and I have not found any access anywhere to get at them without probably ripping into the walls. So my other plan is to rip into the walls and change it to an S or Y plan system by T’ing the tank hot feed from the boiler into the CH hot feed after the pump and installing either a three port mixing valve as the T or two port valves on either side of a standard T. Then I presume I would have to divert the return pipe from the tank into the CH return between the boiler and first/last radiator. I have lots of other questions about this like what happens to the CH header tank/pipework in all of this and what additional controls I would need to do all of this. And if I go that far then should I replace the old boiler for a new condensing boiler at the same time?
I’m an offshore heating and ventilation engineer but I work with air duct systems and electric heater batteries so although I think I’m getting my head around this a bit it’s quite different from my day job.
