Smiths Heater Replacement

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MorrisJohn
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Smiths Heater Replacement

Post by MorrisJohn »

I’m soon going to replace the round smiths bakelite heater in my ‘57 saloon. Apparently it hasn’t worked in ten years. Hot water is getting to it because it feels warm to the touch once the engine has warmed up. The fan however does nothing when the dial is turned.

I have a replacement unit which has been tested on a battery/with water and it works. Once it’s in I can look at the broken one at my leisure. I’ve scoured the forums and can find loads of stuff on heaters but I’m struggling to find the answers to my specific questions - and I believe the manual is scant on detail.

1. I can see the heater is secured in the car by an upper and lower bracket. Are there any further mounts securing the heater in place?

2. At the rear will be the two water hoses and two (little bullet looking) electrical connections? Simple case of disconnecting these and reconnecting to the new unit. Presumably.

3. I’m intending disconnecting the bottom radiator hose and completely draining the coolant before doing the job. The little brass wheel at the rear of the engine will be in the open position so water should also drain back out the heater hoses?

4. I have a multimeter, presumably I should switch ignition on and check the electrical connections at the heater before fitting the new one. What reading should I expect (12V)?

The hoses fitted to my car are all relatively new and in good condition. The car was subject to a major restoration six years ago.

Is there anything else I should be aware of when doing this job? For example, inadvertently creating an air lock or something?

If anyone has any little tips to make it as easy as possible would be appreciated. Sorry if some of these questions seem a bit daft.
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geoberni
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Re: Smiths Heater Replacement

Post by geoberni »

Well I can't be too much help as my '55 has an after market Tudor heater, which has a separate rheostat rather than it being built into the heater case.

But, if the hot water is getting through, can you not disturb a lot less and leave the heater matrix alone?
As I understand it, the heater case is held together with 3 clips; can you not just unclip the front to get access to the rheostat for some basic voltage checks. It's either going to be that or the motor.
You might save yourself a lot of work if it's possible to split it while in the car.

Just a thought....
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MorrisJohn
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Re: Smiths Heater Replacement

Post by MorrisJohn »

Thanks Berni. The front part does indeed just clip on and houses the rheostat. I can certainly remove that and check it for voltage to check that power is getting to it. If it is, I guess I could change the front part first to rule out a failed rheostat. Thanks for the suggestion.

The fan and motor from what I can tell are part of the rear matrix part, so if the fault lies with the motor it’ll need to come out.

Out of curiosity, how hot should the matrix be to touch? Mine gets warm but I can leave my hand on it without it burning me.
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geoberni
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Re: Smiths Heater Replacement

Post by geoberni »

If the pipework isn't gunked up I would expect as hot as the engine water.
My Tudor really belts out the heat. When I first fitted a temp gauge I could drop the temp by a couple of needle widths by opening the heater flaps and putting the blower on.

You could try back flushing it with a hose.

This is what my Tudor is like, Rheostat on left of Speedo.
But aside from that, quite like the round Smiths.
20170905_171618.jpg
20170905_171618.jpg (897.38 KiB) Viewed 1712 times
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MorrisJohn
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Re: Smiths Heater Replacement

Post by MorrisJohn »

geoberni wrote: Thu Dec 02, 2021 6:56 pm If the pipework isn't gunked up I would expect as hot as the engine water.
My Tudor really belts out the heat. When I first fitted a temp gauge I could drop the temp by a couple of needle widths by opening the heater flaps and putting the blower on.

You could try back flushing it with a hose.

This is what my Tudor is like, Rheostat on left of Speedo.
But aside from that, quite like the round Smiths.
20170905_171618.jpg
That looks very smart. Thanks again. Excuse my stupidity but how exactly would I back flush it with my hose?
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geoberni
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Re: Smiths Heater Replacement

Post by geoberni »

:) One of those expressions you either know or you don't. :)

Essentially it means flush it through in the reverse of the normal flow.

Your car is probably the same as mine.
Heater pipes..JPG
Heater pipes..JPG (141.1 KiB) Viewed 1702 times
Basic principle
1 - Close Tap A.
2- Remove Rad Cap, and refit with a section of plastic bag over the hole. That will stop the inward release valve letting air in the top.
3 - Trying not to spill too much, remove B from radiator, hold hose up high and wedge it or have someone hold it up, to stop water coming out of hose whilst you cover exit from Rag with a bit more plastic bag and secure with elastic band.
4 - Connect hosepipe to free end B
5 - Remove pipe from A and point at a bucket
6 - Turn on hose and see what come out of end A.

When finished, reverse the process to reconnect it all and hopefully there'll be no airlocks. :lol:

Of course all that said, It might just be a case that the Tap A isn't open enough....
You could start by taking the pipe from the Tap and see how much comes through the tap.... :-?
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Sleeper
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Re: Smiths Heater Replacement

Post by Sleeper »

I suspect either an air-lock or tap A is full of crud or not opening fully , remove and clean then flush out the heater matrix with the garden hose...

P.S It's winter here...refill with anti-freeze mix.

John ;-)
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Re: Smiths Heater Replacement

Post by jagnut66 »

The fan however does nothing when the dial is turned.
If the matrix is getting really hot but the fan does nothing when the knob is turned then it could well be that the Rheostat is U/S.
I had a similar problem with Sally, except that it was a new replacement Rheostat from a well known supplier.
She had an on / off switch fitted when I bought her, in place of the original Rheostat, which had presumably given up at some point.
So I thought I'd reinstate a Rheostat with a nice reproduction control knob.
It was not to be. I tried two new Rheostats in the end, to no avail. So I gave up and refitted an on / off switch....
Worked first time. :roll:
If you have an on / off switch handy, disconnect from the Rheostat and try it, there's not much to go wrong with them, so even if you want to persevere with a Rheostat, it will at least tell you if the fan motor itself is working.
Of course, check the live and earth wires first, no need for a meter even, a simple electric screwdriver with an earth connection will tell the tale.
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
MorrisJohn
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Re: Smiths Heater Replacement

Post by MorrisJohn »

Thanks for all the replies. I have an on/off switch at the bottom of the dash for some flashing LEDs below the back bumper (which I haven’t got around to removing yet). That switch would be ideal for testing to see if it makes the thing work.

It sounds like doing that and testing the connections is the sensible place to start.
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Re: Smiths Heater Replacement

Post by JOWETTJAVELIN »

Before you do anything else spray a little WD40 onto the heater rheostat switch coil - you will have to manipulate the red spray tube through the heater grille from the side. You will see the cream/grey back of the switch which has some holes in. That is where the WD40 needs to go. They can go high resistance and a little WD often brings them back to life.

Naturally examine the wiring to the heater and check all connections are sound.
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Re: Smiths Heater Replacement

Post by jagnut66 »

Before you do anything else spray a little WD40 onto the heater rheostat switch coil - you will have to manipulate the red spray tube through the heater grille from the side. You will see the cream/grey back of the switch which has some holes in. That is where the WD40 needs to go. They can go high resistance and a little WD often brings them back to life.
Interesting.
But is this a long term solution or does it only work for a while and then you need to repeat the process?
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
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Re: Smiths Heater Replacement

Post by JOWETTJAVELIN »

Essentially about once a year. You can feel on the switch when it wants doing.
MorrisJohn
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Re: Smiths Heater Replacement

Post by MorrisJohn »

Thanks for the tip. I gave that a try but it didn’t work.

I pulled out the heater and found the previous owner when having the car rewired didn’t bother putting the connection in to the heater! Why, oh why I’ll never understand.

Anyway, I drained the radiator by disconnecting bottom hose. Removed old heater unit. Refitted new heater unit (minus electrical connection because I’ll need help with that). I flushed out radiator. Then reconnected bottom hose.

It only took about 3 litres until the radiator was full though, which seems odd? 2 litres of coolant/anti-freeze and 1 litre of water (I had hoped to get a 50/50 mix in there). Should this cause any issues??

I have also succeeded in air locking the matrix, since it’s not warming up like the last one did. I’ll refer to above to try and remedy that.
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geoberni
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Re: Smiths Heater Replacement

Post by geoberni »

Capacity of the Cooling System, including heater, from the workshop manual data (heater is basically an extra pint).
MM (doesn't have a heater figure given) 13¼ Pints
Series II - 10¾ Pints (approx6 ltrs)
1000 - 9¾ Pints (approx 5.5 ltrs)

So it depends how much fluid was left in the rest of the system, but 3 ltr is definitely a bit low in my opinion.
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MorrisJohn
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Re: Smiths Heater Replacement

Post by MorrisJohn »

geoberni wrote: Sun Dec 05, 2021 12:52 pm Capacity of the Cooling System, including heater, from the workshop manual data (heater is basically an extra pint).
MM (doesn't have a heater figure given) 13¼ Pints
Series II - 10¾ Pints (approx6 ltrs)
1000 - 9¾ Pints (approx 5.5 ltrs)

So it depends how much fluid was left in the rest of the system, but 3 ltr is definitely a bit low in my opinion.
Thanks Berni. I thought it should have taken more. The heater was air locked after putting it back together, there was no water in it. I closed the tap and removed hoses to check. So I guess that accounts for some of the discrepancy. The radiator is definitely filled right up though.
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Re: Smiths Heater Replacement

Post by JOWETTJAVELIN »

There will be coolant left in the engine water jacket. It’d never take the full complement unless all totally dry. Just run it a short distance and re-check the coolant level. The air lock you suspect should work its way out - they’re not notorious for it.
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Re: Smiths Heater Replacement

Post by MorrisJohn »

JOWETTJAVELIN wrote: Sun Dec 05, 2021 1:12 pm There will be coolant left in the engine water jacket. It’d never take the full complement unless all totally dry. Just run it a short distance and re-check the coolant level. The air lock you suspect should work its way out - they’re not notorious for it.
That makes sense, thanks. I’ll do that. Could be a while though as the roads are all salty now.
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Re: Smiths Heater Replacement

Post by jagnut66 »

When I replace my coolant I always run it for a while (1/4 to 1/2 hour on the driveway) with the radiator cap off to let it find it's way round and 'burp' itself :P, it's worked for me so far.
Then, as you say, top up as required.
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
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Re: Smiths Heater Replacement

Post by MorrisJohn »

You were right gents. A combination of flushing the replacement heater with a hose and letting the car run for a while has got rid of the air lock. The matrix is nice and hot now with the engine running.

Just need to sort out the electrical connections now.
A bad day with my Volksie still beats a good day at work!

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