Front room radiator never gets hot

ThisIsWeird

FreeBear said:

Grenage said:

It may be as simple as the radiators need balancing.  Google the process, it's not too complicated.

But to balance radiators well does need some equipment. Doing it by feel is way too inaccurate, and an IR thermometer is also a waste of time. A cheap way to to grab a couple of LCD thermometer modules such as https://www.ebay.co.uk/itm/256406321943 (also available from other online merchants). Use an old pipe clip to hold the sensor in contact with the pipes, and you're all set to go. Picture attached.

I like!
Do the sensors need to be in direct contact with the pipes, do you reckon? If not, but one is a mm or two further away, what temp difference could it make I wonder?

Grenage

ThisIsWeird said:

FreeBear said:

Grenage said:

It may be as simple as the radiators need balancing.  Google the process, it's not too complicated.

But to balance radiators well does need some equipment. Doing it by feel is way too inaccurate, and an IR thermometer is also a waste of time. A cheap way to to grab a couple of LCD thermometer modules such as https://www.ebay.co.uk/itm/256406321943 (also available from other online merchants). Use an old pipe clip to hold the sensor in contact with the pipes, and you're all set to go. Picture attached.

I like!
Do the sensors need to be in direct contact with the pipes, do you reckon? If not, but one is a mm or two further away, what temp difference could it make I wonder?

A huge difference, I would imagine.

FreeBear

Grenage said:

ThisIsWeird said:

FreeBear said:

Grenage said:

It may be as simple as the radiators need balancing.  Google the process, it's not too complicated.

But to balance radiators well does need some equipment. Doing it by feel is way too inaccurate, and an IR thermometer is also a waste of time. A cheap way to to grab a couple of LCD thermometer modules such as https://www.ebay.co.uk/itm/256406321943 (also available from other online merchants). Use an old pipe clip to hold the sensor in contact with the pipes, and you're all set to go. Picture attached.

I like!
Do the sensors need to be in direct contact with the pipes, do you reckon? If not, but one is a mm or two further away, what temp difference could it make I wonder?

A huge difference, I would imagine.

To get an accurate reading of water temperature, the business end of a sensor should be in the middle of the pipe. This way, you avoid the heat losses that occur at the periphery of the pipe. But when balancing a radiator, all we are interested in is the difference between flow & return temperatures and can ignore boundary losses as they should be virtually the same on both pipes.

Having an air gap between the sensor and pipe introduces an error caused by air flow, and may not be the same on both pipes. With the setup in my previous post, errors will be introduced because the sensor is not in full contact with the pipe, and one side could be subject to a cooling air flow. These errors are likely to be less than 0.2°C, so plenty close enough. If you want a more accurate reading without inserting a thermowell in each pipe, the next best is a clip-on sensor (see image below), or a thermal ribbon wrapped with insulation.

400ixl

Typically you can balance them without any thermometers to get a good enough job done. Fine tune it if you wish with such equipment, but I doubt you will bother once you get it working.

Give it a try first, costs you nothing. If you then need to fine tune then get the thermometers.

FreeBear

400ixl said: Typically you can balance them without any thermometers to get a good enough job done.

I disagree. A finger doesn't have the sensitivity to get anywhere close. At best, you'll get "meh, kinda feels like it", but it will be different for each radiator. At worst, an ineffective and inefficient heating system.

For just £6, you can get a pair of thermometer modules that will get you within 0.5°C. Not really any excuse to get a pair. Once the radiators have been balanced, they can be used to keep an eye on room temperatures or popped in the freezer & fridge.

Clip-on sensors and thermowells bump the cost up, and for those that are not OCD about precision, probably over the top. I've got a couple of thermowells close to my boiler as part of a heat meter setup to monitor energy output (hey, I like to know in real numbers what stuff is doing). And also gone as far as using clip-on sensors to fine tune the balance.

ThisIsWeird

I agree - it's a simple but time-consuming job, and justifies the low cost of proper thermometers that should remove the guesswork.
No point faffing - make life easy.

FreeBear

ThisIsWeird said:

I agree - it's a simple but time-consuming job, and justifies the low cost of proper thermometers that should remove the guesswork.
No point faffing - make life easy.

Currently "faffing" and getting nowhere. Couldn't get the ∆T close to the 15°C target I was aiming for. Crack the valves open less than an eighth of a turn, and ∆T was around 12°C or worse.

Turn the pump speed down folks - It makes the job so much easier. My pump had been set to maximum speed, and currently running at 70%. Will drop it down to its lowest setting and have another go tomorrow.

moneysaver

FreeBear said:

400ixl said: Typically you can balance them without any thermometers to get a good enough job done.

I disagree. A finger doesn't have the sensitivity to get anywhere close. At best, you'll get "meh, kinda feels like it", but it will be different for each radiator. At worst, an ineffective and inefficient heating system.

For just £6, you can get a pair of thermometer modules that will get you within 0.5°C. Not really any excuse to get a pair. Once the radiators have been balanced, they can be used to keep an eye on room temperatures or popped in the freezer & fridge.

Clip-on sensors and thermowells bump the cost up, and for those that are not OCD about precision, probably over the top. I've got a couple of thermowells close to my boiler as part of a heat meter setup to monitor energy output (hey, I like to know in real numbers what stuff is doing). And also gone as far as using clip-on sensors to fine tune the balance.

Can you post a few links of the items in bold. I am a bit OCD and fancy giving it a go with the correct equipment.

Thanks

Moneysaver

FreeBear

moneysaver said:

FreeBear said:

400ixl said: Typically you can balance them without any thermometers to get a good enough job done.

I disagree. A finger doesn't have the sensitivity to get anywhere close. At best, you'll get "meh, kinda feels like it", but it will be different for each radiator. At worst, an ineffective and inefficient heating system.

For just £6, you can get a pair of thermometer modules that will get you within 0.5°C. Not really any excuse to get a pair. Once the radiators have been balanced, they can be used to keep an eye on room temperatures or popped in the freezer & fridge.

Clip-on sensors and thermowells bump the cost up, and for those that are not OCD about precision, probably over the top. I've got a couple of thermowells close to my boiler as part of a heat meter setup to monitor energy output (hey, I like to know in real numbers what stuff is doing). And also gone as far as using clip-on sensors to fine tune the balance.

Can you post a few links of the items in bold. I am a bit OCD and fancy giving it a go with the correct equipment.

Thanks

Moneysaver

This is rabbit hole that could go very deep and cost quite a bit of money, especially when you start wanting to log the data.

thermometer modules: https://cpc.farnell.com/dfrobot/fit0507/waterproof-digital-thermometer/dp/IN09528

Clip-on sensors: https://atcsemitec.co.uk/product/pipe-clip-surface-temp-sensors/

thermowells: https://www.awe-ltd.co.uk/products/temperature/temperature-sensor/thermowell-temperature-pocket-tpp.html

Note, the thermowells are intended for use with a pipe fitting such as a branch tee such as this - https://www.cityplumbing.co.uk/p/compression-female-branch-tee-22mmx22mmx12/p/950327

Shop around on your preferred market place, be it Amazon, Ebay, Aliexpress, or CPC/Farnell. Most of this stuff is relatively inexpensive. The only one likely to cause problems is the thermowell & fitting - I ended up getting a branch tee & reducing bush from CPS and making my own pocket out of a lump of bronze (have a lathe or two, so a trivial turning exercise). Due to the amount of work involved, best left for permanent installations where data is being recorded (I use one with a heat meter linked to a home automation system).

If you have a bunch of the clip-on sensors (or other 10K NTC probes) and want to log the data, have a look for the Eletechsup NT18B07 board. You can connect up to 7 sensors to it and use a MODBUS/RS485 interface to read the data. Shop around and you should find it for less than £10.

One comment to make about the clip-on sensors - Make the lead at least 500mm long. I didn't, and it means having to rest the thermometer module on a box.