Electric floor warming

[Dill]

Re: I confess that I realise now that we have never tried it without EHU so will switch back the cable to the 'inverter input' socket as it was before, see if the air con works again"

 

I can confirm that the air con now works again :-)

[Dill]

Re: then disconnect the EHU and see if that works!

 

I can confirm that the air con work without EHU.

 

The underfloor heating rocker switch on/off bulb is now not illuminated suggesting that this isn't working also. This may take a while to cool down so will report back later!

[Dill]

As another aside, I have just remembered, that when they replaced the inverter we gained another 230v 3 pin socket as they were unable to get the inverter to power all sockets.

 

As the inverter never worked I don't actually know if this was possible before in any event but I am wondering if this is connected to this from my previous post:

 

"I have also since found another white cable in the 'electronics locker' which looks like it should be plugged into something but has later been removed? This is to the left of the Waeco Perfect Power Accessory unit. Pic follows:"

 

Someone else mentioned in passing that if they had replaced the Waeco with another Waeco it would have saved them the time of having to rewire. Sadly I didn't think to probe any further so not sure exactly what re-wiring would have had to take place and if there was more functionality with the Waeco unit which we are now missing?

[spirou]

To summarize, at least as I understand things (but I'm a bit lost by now):

 

The waeco unit is wired to inverter and powers the AC.

 

Inverter is also wired to the floor heating voltage transformer but not via the waeco unit. There must be a separate connection as it started to work when you turned the inverter back on.

 

Waeco unit has no connection to EHU.

 

Both AC and floor heating should thus work on battery power alone. Since you thought they only work on EHU you never tried without. Which is actually a good thing as both will flatten the battery in very little time. You made the battery charger/power supply unit work harder and incur some transformation losses on the inverter rather than just passing through EHU.

 

Am I close?

 

But now I'm thinking why couldn't (they) just wire both the AC and floor heating via waeco unit as it was designed to? So you would have inverter in, EHU in, AC out, floor heating out.

[Derek Uzzell]

The images below show the input and output ends of a Waeco SinePower SP1500 inverter. 12V DC input would come from a motorhome’s leisure-battery and the inverter would provide 230V AC output from a single outlet socket. There’s the option to connect a remote control.

 

Assuming that the Waeco VS-230-2-K ‘switching’ unit was installed when the Hymer was built and its purpose was to allow the floor-heating to run off the leisure-battery when a 230V EHU was unavailable, the VS-230-2-K unit should have had a connection to the EHU power-supply as well as to the inverter. (The ’spare’ white cable near the Waeco switching unit?)

 

Otherwise, if Hymer’s intention had been for the floor heating to function only when the motorhome was connected to a 230V EHU, an inverter and the Waeco switching unit would not be needed - the floor heating’s transformer could simply have been connectetd to a 230V AC supply that would become live only when the motorhome was connected to an EHU.

 

Although it was established that the inverter needs to be switched on for the floor-heating to operate, Dill has said that, when the Hymer was disconnected from the EHU, the rocker-switch for the floor heating no longer illuminated - which suggests that the floor heating may not be operable ‘off EHU’.

 

The choices seem to be to leave things alone, but to do some basic testing to confirm whether or not the floor heating only works when the Hymer is connected to an EHU (It’s known that the air-con will work off-EHU) or to do some significant rewiring.

 

[Dill]

Wow, thanks for all the input.

 

I think, now that the floor heating is working, we will leave well alone as I am not keen to have the ability for the heating to work when not on EHU in any event!

 

One thing I would like confirmed if possible. The transformer seems to get warm when the floor heating is on, and the longer it is on, the warmer it gets as per the floor. I am assuming this will reach a certain point and not get hotter lol! (lol) To give it some context, I would say it gets quite hot to touch but whether this is too hot or not (overheating) I don't know.

 

The question is, should this box get hot? If yes, is it ok to go out and leave the underfloor heating switched on or...?

 

If the answer is that it shouldn't get hot, I'm guessing something is wrong with the unit or the wiring somewhere and it shouldn't be used?

 

Thanks again for your continued support :-D

[spirou]

As I've never actually used ours I have no idea (also, not quite the same transformer). I imagine it could get very warm but not hot. Possibly poor ventilation or faulty fan if there is one inside?

[Dill]

Hmm I can't see any evidence of a fan, and I certainly haven't heard one kick in. The unit is in the habitation area, under seat storage area, so plenty of room around it although we do use this space to store our pressure cooker! (lol)

[Derek Uzzell]

You might want to look at this link

 

https://acupwr.com/blogs/news/119522307-transformers-get-warm-don-t-panic

 

It would be perfectly normal for your Hymer’s transformer to warm up when the floor heating system is running. The longer the floor heating continues the warmer the transformer will become, but the system should ’self regulate’ so that the floor does not become too hot and the transformer does not overheat.

 

Suggest you leave the heating system on for a few hours and check (say) every half-hour how hot the transfomer and floor are. As Spirou says, thre transformer could get pretty warm, but not so warm that you cannot keep your hand on it. (Your photo does not appear to show any visible signs of the transformer having overheated in the past.)

 

Most people are probably happy to connect their motorhome to a campsite EHU and leave it unattended with its battery-charger running, and its fairly common for a motorhome parked at home to be connected to a domestic mains power-supply so that the vehicle’s batteries are being charged 24/7 for extended periods. So when you test your floor heating system, if there’s no sign of the floor or transformer becoming worryingly hot, it should be OK to leave the system running indefinitely. Obviously there’s a risk that the system might malfunction, but the only way to avoid that would be to switch the system off when you aren’t there to keep an eye on it.

 

Make sure when you put stuff in the under-seat storage area that the transformer has plenty of air-space around it to allow it to radiate heat, and ensure that it can’t be covered or hit by what you store there.

 

This 2006 forum discussion may be of interest

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Underfloor-Heating/4185/

[Keithl]

Correct me if I'm wrong but as I understand the U/F heating transformer is working from the output of the inverter which in turn is taking 12 volt power from the PSU. Correct?

 

If so then is the inverter a Pure SIne or Modified Sine output?

 

If modified then this may be the reason your transformer is getting hot.

 

I may be wrong on my initial assumption but things seem to have gone round in circles and you clearly said the U/F heating only works with the inverter turned on!

 

Keith.

[Derek Uzzell]

Dill’s motorhome is a 2009 Hymer B675 SL model and its specification is listed here

 

https://www.outandaboutlive.co.uk/motorhomes/buyers-guide/motorhomes/details/675-sl/2904

 

It would seem that much of the ‘habitation’ electrical equipment is housed in an externally-accessible locker (which Dill refers to) as exemplified in the image attached below, but the transfomer that is connected to the floor-heating system is in a seat-base above the locker.

 

What exactly the Hymer’s original electrical installation was is unknown. It has been assumed that the transformer and Waeco ‘switching’ unit are original and Dill has said that a Waeco SinePower SP1500 inverter (presumably originally fitted by Hymer) was replaced at some stage. Dill said that the replacement inverter is a “sunsloar” product, and I’m guessing that it might be this one

 

https://www.sunshinesolar.co.uk/Item/VP1500?gclid=EAIaIQobChMIjt_m9_C55wIVWODtCh0R_Q9REAAYASAAEgLcTfD_BwE

 

The Hymer has an air-conditioner, but it has not been stated whether this was factory-fitted when the motorhome was built or retro-fitted subsequently. If the present inverter is the VP1500 device, this has two output sockets (as opposed to a Waeco SinePower SP1500’s single output socket) so the floor-heating and air-con COULD be being powered separately. The K01 Remote Control unit (in Dill’s photo on Page 1 of this thread) appears in several places on-line (example here)

 

https://www.omvormer-omvormers.nl/contents/nl/p317.html

 

and adverts usually mention its use with pure sine-wave inverters. However, whether the present inverter is pure or modified sine-wave type, it should be expected that the transformer would warm up significantly when operating as that’s what transformers do.

 

The reason this thread has “gone round in circles” is severalfold

- there’s (apparently) no on-line in-depth knowledge of the floor-heating system fitted by Hymer

- Dill’s Hymer’s electrical system has been modified

- Dill is not a motorhome-electrics ‘geek’

 

A step-by-step examination of the Hymer’s present electrical system should establish what’s going on, but I don’t think it would be practicable to try to remotely talk Dill through such a process.

 

I still don’t understand why the floor-heating only operates when the Hymer is connected to a 230V EHU but needs the inverter to be switched on as well. Or why the Waeco VS-230-2-K switching unit only has one input cable. But if Dill can get the floor-heating and air-con to work OK, that’s what really matters...

[Dill]

Derek, you are absolutely right in all that you say above. Once again thank you for your continued support.

 

Just for clarity and to confirm that the inverter is indeed a pure sine wave one which was replaced recently under warranty after our purchase of the van.

 

The transformer does indeed increase in temperature but maxes out and does not appear (by touch, look and smell) to be overheating.

 

I believe the only modification to the wiring in the 'electrical' locker appears to be the new inverter as mentioned previously.

 

An inventory of the locker follows:

1) Schaudt OVP01 - overcharge protector (3 sockets, if this is the right term)! From what I can ascertain;

2) Generic white unmarked box (This white box is smaller than the transformer which sits directly above it, but under the seat in the habitation area).

3) Schaudt LA1210 - Battery charger

4) Schaudt 101c Elektroblok

5) Schaudt LR1218 Solar Controller

6) Waeco ECL-102 - Charging current distributor for use with air-con

7) Waeco ECL-100R - another charging current distributor?

8) Inverter - Sunshine 1500w pure sine wave

9) Waeco power accessory

 

The B675 SL is the BestLine model which came with underfloor heating and air con as factory fitted extra.

 

As you quite rightly sign off with, the underfloor heating, air con and all other electric appliances work so I'm a happy bunny lol. That said, I have enjoyed and learned so much from this thread I'm not sure I will rest until I understand how all the units work together! *-) (lol)