Central Heating run time

[DerbyBorn]

I have often thought it would be useful for monitoring purposes to be able to see how many hours the central heating is running for on a day by day basis. This would show the effect of thermostat settings, weather, occupancy, etc.

With a conventional system guess some sort of clock wired across the pump could show the hour run = but not so easy with a combi where the pump is used in HW mode.

An add-on wireless module would be good to integrate with the room thermostat = logging demand duration.

Is this a daft idea - or does it have any merit and has anyone tried it?

[Dave Liquorice]

I have hours on for the stove, solar, boiler, house CH and barn CH. Done via mains relays across each relevant circuit to provide isolation with the contacts feeding into the inputs of a 1-wire DS2408 8 channel addressable switch. That is connected, along with a few temperature sensors, to an Embeded Data Systems OW Server that does the 1-wire donkey work and squirts the current data every minute over ethernet to a script running on the server that logs it.

It's interesting and means I can see what is on and how often/much without getting up via a web page on the server. TBH ona conventional system I can't see it having much value but with mine I can see how the solar and/or stove hold the boiler off by keeping the thermal store hot.

[chris French]

In message , DerbyBorn writes

ISTR Andrew Gabriel has rolled his own CH controls that do this sort of logging.

The Heatmiser wifi programmable stat can do as well. Heatmiser sell a unit that can be used to link multiple stats, and can log running time. But the protocol is published and there are open source projects that can log the same data, control the stat etc.

[Harry Bloomfield]

DerbyBorn pretended :

I get a rough idea from a weather station which records all of its data and produces graphs. I can see from the indoor temperature graph when the heating fires up and roughly for how long, when the line on the graph rises.

It also shows a rise when cooking is under way as does the humidity, when she forgets to turn the extractor on :/

[Andrew Gabriel]

Yes. A computer does the functions of the timeswitch (and manual override) and also the roomstat. I have logs going back 10+ years for much of this data, plus the outside temperature.

The pump is probably not very useful to monitor due to pump overrun, and that it will be running when the boiler isn't firing. You want to record the demand for heat from the stat, and the energy used by the boiler.

On an older non-modulating Potterton Profile, this is easy - I simply have a relay in parallel with the main burner solenoid, so I can record the burner on/off times. For a modulating burner it is harder - I did a prototype which logged the 4 burner power level LEDs, but I didn't ever put it into real service. A pulse gas meter would probably be easier to record and give more accurate data.

[Nick]

Perhaps a daft question and not meant to be derogatory to you or others in this thread but why do you want to accumulate and monitor this info? Devil's advocate perhaps. You can heat your house, or parts of as chosen, presumably quite effectively. When you have acquired the monitored info and processed it.... what do you do with it and will you be any better off for doing so? You may well then have a far better understanding of your heating system but you will have lost a considerable amount of your life that could have been spent more advantageously. Just my 2d. I'll get my coat and tin hat, Nick.

[DerbyBorn]

A good point Nick. I don't want to get too anal about it - it would be interesting to know that today I used less heat than the same day last week and similar such headline snippets of info. A friend has solar panels and his monitor display gives him a daily info that is mildly interesting. My heating is controlled with a programmable thermostat - I can reach out and touch a radiator to see if it is heating or not - but I would like something a bit better (until the novelty wears off)

[Andrew Gabriel]

Here's mine so far this week:

Date heating on call for heat hot water burner on Energy Cost (HH:MM:SS) (HH:MM:SS) (HH:MM:SS) (HH:MM:SS) (kWh) (£.p) 8 Dec 6:02:26 6:02:26 0:00:00 2:13:50 40.37 3.40 9 Dec 1:40:18 1:40:18 0:30:14 0:44:59 13.57 1.14

10 Dec 3:33:53 3:33:50 0:17:04 1:39:42 30.07 2.53 11 Dec 6:26:02 6:26:02 0:00:00 2:47:46 50.60 4.26 12 Dec 7:31:19 7:31:18 0:11:07 2:58:21 53.80 4.53 13 Dec 4:37:47 4:37:47 0:00:00 1:40:15 30.24 2.55 14 Dec* 2:33:34 2:33:35 0:00:00 0:50:29 15.23 1.28

• until 14:00 only.

Note that the "Heating on" column matches the "call for heat" column, because radiator temperature has been set to output right amount of heat, and there's been no overshoot requiring the room stat to click off.

This is probably a worse week than normal, as I've been working (at home) until well after midnight most nights.

[DerbyBorn]

[e-mail] (Andrew Gabriel) wrote in news:l8hoph$8kg$ [e-mail]:

surely on a milder day then the call for heat would reduce - alternatively their is not enough output to satisfy on a cold day.