Options for 1960s hot-air central heating

A relative has moved into a 1960s house with an original Johnson & Starley hot-air heating system (sorry, no part number to hand). System has been inspected by a gas technician and pronounced OK. System has separate air-heater and water-heater burners. Neighbours with similar systems like them, but I'm concerned about running costs.

I have a few concerns:

- The air-heater pilot light flame is quite large and noisy, and is presumably wasting lots of gas by modern standards.

- The electric rotary timer that controls the water heater doesn't rotate anymore, so the water heater comes on whenever the tank thermostat commands it.

- Based on meter readings, I think the cost of water heating and the 2 pilot lights will be about £500/year, before any hot-air heating is costed.

Any thoughts on following to reduce costs?

- Replace the timer for the water-heater (the part alone costs about £100).

- Turn off pilot light for air-heater during summer.

- Replace entire system with new hot-air or radiator-based system.

Reply to
LumpHammer
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Generally reckoned to be up to 18% cheaper than water based systems.

Fit a pollen filter, have it overhauled and have any non-working parts replaced.

Colin Bignell

Reply to
Nightjar

I think you're about to discover that installing a modern, efficient 'green' system will cost £shedloads; so much so that the possibility of not getting the money back before the new system packs up and needs to be replaced is quite high.

OTOH, if the current system has been installed since the 60s, and in its own terms is running well, then that at least suggests leaving it in place to see how things go over a full heating season might be an idea. OK, you've got some minor replacements to make (the timer clock), but there are plenty of experts in these matters on the group who could advise on what to replace the failed unit with. If you have access to a service manual, check the pilot lights for proper burning such as height of flame, as well as other checks and tests that might need to be performed.

With the heating season coming to an end, turning off the air-heater pilot is a good idea, and over the next few months you'll get a good idea of the costs of DHW. Is the cylinder fitted with an immersion? It could be cheaper just to use that, turning the gas off altogether, but you'll need to take into account the usage patterns and relative costs of gas and electricity. Is the tank well lagged? Could you add more (including pipe insulation in the take-off run from the tank)? It'll be quite cheap. Make sure the tank stat is functioning properly and not turned too high (60C as a minimum).

So, I'd say see how things go, if all the neighbours still have the system in place that says a lot about it. Don't make hasty, uncosted decisions. Your relatives might well find they love it.

Reply to
Terry Fields

Did they just look at the gas part and do they have the required knowledge (and certification) to inspect 50 year old gas appliances? An installation that old also rings an "asbestos insulation" alarm bell with me.

Modern stuff doesn't have constantly lit pilots so yes it's wasting gas.

Should be easy to fix with almost any single channel timer for around £30, might need a bit of wiring adjustment but spending £100 on a like for like(?) replacement is daft. What is the reheat time for the HW from more or less cold. Just heating the HW manually when required rather than on a time switch does save energy. The time switch on the HW in a flat I had broke, switched to just heating the water manually and there was a noticeable drop in the gas bill. Reheat time was about 20 mins and the cylinder would stay hot enough for washing for about 48 hrs but I was living on my own so HW demand not very high.

Depends if the location, insulation etc of the property does give a sensible "no heating ever required" period. The last couple of days here have been sub 10 C and the heating is kicking in. Begining of last week was glorious up near 20 C and no heating...

Might be worth looking at but also in conjunction with insulation etc to retain the heat produced. Loft, cavity wall, double glazing, well insulated HW tank, draft proofing, etc. The better return may well be from insulation measures not replacing the heating system.

Reply to
Dave Liquorice

I'd have thought the pilot light system would have some mod kit to allow it u to use an igniter when its needed as a naked flame on all the time is seemingly not considered good these days. Brian

Reply to
Brian Gaff

As mentioned below, asbestos insulation around the heat exchanger is likely to be the real problem and the reason why the neighbours have not changed their heating system(s). Dave

Reply to
snot

I have the same system but mine was installed in a new build in 1991.

I also have 2 pilot lights, the hot water one use 3 kW of gas a day and the heating one 5 kW of gas a day.

I enquired about a pilot light substitute but none.

They still use pilot lights on new units.

There is also no tank stat as the water temp is controlled by a knob on the hot water part.

I turn the heating pilot light off in the summer. Also the electric to it as the hot water does not need electricity.

There is no timer for the hot water on mine, the hot water tank is well insulated and if no hot water is used, (went away for a day but ended up away for a week, had just read my meter before I went) , it uses 2 kW a day to maintain the temperature.

Total consumption of gas a day is 17 - 20 kW for hot water, (2 power showers and dish washing a day), cooking and pilot light.

Gas used for heating varies up to 130 kW in a day, 24 hours when outside temp was -20 C. usually use between 18,000 and 20,000 kW of gas a year for heating and hot water.

I don't bother with the timer for the heating as almost instant heat, get up turn thermostat to 21 C and turn to 16 C when got to bed as house is occupied all day by 2 OAPs.

Put a ~£20 timer in series with the tank stat.

Yes.

How many years/decades will it take to recoup the costs?

Reply to
Ron

Put in a modern wet system (radiators). There are various subsidy schemes on at the moment to help with costs. This hot air sytem was a passing fad that lasted about six or seven years ISTR. There is serious money to be saved on the gas bill if a correctly sized modern installation is fitted.

500/year for hot water is ridiculous. Go and see the neighbour's gas bills over a year. See several of them if possible. Do all the other stuff as well, D/glazing, insuation, draughtproofing etc.

ISTR there were some serious incidents with these systems when the heat exchanger failed/corroded and gas combustion products/CO got into the home.

Pilot BTW is adjustable on many gas systems. Small screw on the gas valve assembly. It needs to be big enough to heat the thermocouple but not so small it keeps blowing out. Gas man should have fixed this. If it's too big, uses more gas and may burn out the thermocouple. You certainly shouldn't be able to hear it.

Reply to
harryagain

Where do you live to get -20 C ? Almost unheard of in the UK. Only v/large house would use 18,000Kwh gas ina year in UK. Or v/crap insulation

Reply to
harryagain

Where do you live to get -20 C ? Almost unheard of in the UK.

I never said it was -20 all the time, that was a one off about 18 years ago.

I take it you don't live in Scotland?

Only v/large house would use 18,000kWh gas in a year in UK.

I take it you don't live in Scotland?

One year I used 23,000 kWh of gas in a year.

You do realise to get an average consumption of gas a year of 16,500 kWh some people have to use more than that especially in Scotland where it is colder than England.

See first hit pdf file in this search page.

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Reply to
Ron

Indeed - January 1996.

Reply to
charles

Put a ~£20 timer in series with the tank stat.

Yes.

How many years/decades will it take to recoup the costs?

Reply to
dennis

If you keep it, it's definitely worth installing their "ModAirFlow" addition if it's not already fitted. This makes the fan speed and heating gas jets variable depending on the actual v desired temperature difference, rather than either fully on or off. It cuts down the fan and heater noise, and drafts from the vents in normal use and when it kicks in.

Reply to
Reentrant

They're ok if you dont mind the noise & slight dust dusturbance.

I sure hope not. If your figure's right, something needs attention.

versus spending the £30 for a timer on insulation... probably the insulat ion would save more

yup. Where does its heat go in winter, into the house or all up the chimney ?

costly, and you get rads instead of vents. Hot air blows any smells about a nd makes a noise, but in other respects is probably better.

NT

Reply to
meow2222

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