Only 4-wire probes have any chance of an accurate zero ohms reading. Even my expensive LCR meter has an offset. Does yours not?
Immersion heater not heating?
- Thread starter UseLeSsDiYr
- Start date
Only 4-wire probes have any chance of an accurate zero ohms reading. Even my expensive LCR meter has an offset. Does yours not?
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Obviously not. Not that I pay a single penny for any of my tools though
For this purpose its only a simple reading of resistance needed.
If its an ohm or two out then it does not really matter.
But if the test leads measure 1.6 ohms then you just deduct that from the actual reading shown to get close to the real resistance.
Tony
If its an ohm or two out then it does not really matter.
But if the test leads measure 1.6 ohms then you just deduct that from the actual reading shown to get close to the real resistance.
Tony
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On measurements when fault finding on old boilers with a thermocouple then an exact measurement of very low resistances is very important.
But mostly this can be done by measuring the voltages rather than resistance as that's usually easier and not affected by test lead resistance.
Tony
But mostly this can be done by measuring the voltages rather than resistance as that's usually easier and not affected by test lead resistance.
Tony
Thanks for everyone's input.
I decided to pop out and pick up a replacement stat, now fitted. At least I now have one which has a reset switch and complies with current regulations!
The old one had a rattle too; something is loose inside.
After 30 - 60 mins, the water is still not hot, not even warm, but only very slightly luke-warm. o I guess the element's gone? Will this be easy to replace?
I assume the on/off switch is not the culprit here, is it?
I decided to pop out and pick up a replacement stat, now fitted. At least I now have one which has a reset switch and complies with current regulations!
The old one had a rattle too; something is loose inside.
After 30 - 60 mins, the water is still not hot, not even warm, but only very slightly luke-warm. o I guess the element's gone? Will this be easy to replace?
I assume the on/off switch is not the culprit here, is it?
Let's go one step further here....set your meter to Volts AC, 600v - that's just about at 1 o'clock on your meter. With your mains switch on, put the red meter lead onto the brown thermostat terminal, and the black meter lead onto the blue terminal. You should see 250v here on the meter scale.
This will tell you if the main switch is working.
CAUTION......these are high mains voltages you are trying to measure. If you are uncomfortable with this, please call it a day, and get someone in.
We can continue with your testing if you like, but only if you are happy with what you are doing.
John
This will tell you if the main switch is working.
CAUTION......these are high mains voltages you are trying to measure. If you are uncomfortable with this, please call it a day, and get someone in.
We can continue with your testing if you like, but only if you are happy with what you are doing.
John
Hi John
So I shall leave the power coming through the main fusebox ON, then switch ON the water heater, followed by placing the red and black probes as you've directed?
This wouldn't fry me or short circuit anything, will it? I assume if there's a light on the heater switch, electricity is flowing through?
Regarding the element, how do I know size I need? The original stat is 7 inches.
Thanks
So I shall leave the power coming through the main fusebox ON, then switch ON the water heater, followed by placing the red and black probes as you've directed?
This wouldn't fry me or short circuit anything, will it? I assume if there's a light on the heater switch, electricity is flowing through?
Regarding the element, how do I know size I need? The original stat is 7 inches.
Thanks
The red lamp on the switch would indicate that it's working for sure, but that is the way to test it!
Before you do though.....switch everything off and tell us what resistance you find through the element itself, will you?
John
Before you do though.....switch everything off and tell us what resistance you find through the element itself, will you?
John
The washing machine's on at the moment. Another 40 mins before I can power down the mains supply.
At what settings do I test the resistence on the element (grey & blue?)?
Sorry for all these newbie questions.
At what settings do I test the resistence on the element (grey & blue?)?
Sorry for all these newbie questions.
Electric elements have a low resistance......I can't quote what yours will be, but say 50 ohms or less.
Set your meter on the 200 ohm setting, and see what reading you get.
(Immersion heaters are either 11", 14" or 27" long so we don't know which you have until it's removed, if it becomes necessary).
John
Set your meter on the 200 ohm setting, and see what reading you get.
(Immersion heaters are either 11", 14" or 27" long so we don't know which you have until it's removed, if it becomes necessary).
John
Whilst I'm waiting, does anyone know which valve I've need to use to drain the water from the cylinder?
Red or green? I think the water inlet is from the green pipe, so I'd imagine the drainage would be the red valve?
Red or green? I think the water inlet is from the green pipe, so I'd imagine the drainage would be the red valve?
I feel compelled to take the day off work tomorrow to fix this problem
It's through the side, about a feet off the ground.
The original stat length was 7 inches.
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