[Spruce]

Firstly chaps-tanks for your responses and suggestions. Spruce-your post is spot on.

I've just got back from GTC Marine, based at RAF Alconbury who are a webasto agent. I'll try and explain what he replaced and commented on with regard to the heater.

Spruce is spot on in saying that the unit is designed to cycle CONSTANTLY. So when I turn off my pole tap, the temperature of the unit increases to 81 degrees and then cuts out to half heat as there is no water cycling through. In the marine industry these units run with a constant flow of water through them for a boiler and rads. I have the 9kw heater and this enough to run a boat with a boiler and 9/10 rads plus.

Because of the intermittent usage, my heater turned off and on 1083 times causing the burner to coke up and die. I had to have the burner unit and fuel sensor replace, however the coil wasn't required, costing £350. I will be going after webasto to see if I can get it under warranty.

Gary's comments were suggesting a remote sensor that as soon as the pole tap is turned off, there may be a way to fit a remote sensor to flip the heater over to cycling the water, or having a separate tank that has a cold supply and is drawn into the heated section like a header tank.

Te unit has only lasted 18 months which I'm very disappointed at, considering the cost. I've got to come up with some way of cycling the steer floe to keep the heater on cycling and the temperature from creeping up. Either that's or put the heater on before I go out and then use the already heated water

He felt that the 9kw was definitely over kill for the use we have and as a single operator, there were other options. I'm not mechanically minded at all, so have to refer to others expertise on this, but pure freedom seemd very resigned to the fact that this was a hazard of the unit after this sort of use. (Which I don't view as particularly excessive)

This isn't a pure freedom dig by the way, as Andrew has been great when required, just disappointed that I may have to fork out every couple of years if I keep the diesel heater.

Steve

Hi Steve.

The way I understand it is that Ionics have a pressure relief valve fitted on the heated water side going to your reel. It will have a blowoff pressure set below the pressure switch or controllers cutout. Once you switch the tap off at your pole the pressure will build up a bit and then be released into your water tank. Downside is that the pump will be running all the time.

Personally, I also think that the 9KVA heater is too powerful for this as well, so you may even have engineer something else as well to bleed off more heat from the heater circuit. Last night I saw a company advertising a finned tube heat exchanger
 http://www.turnbull-scott.co.uk/industrial_heat_exchangers/finned_tube/
that could be fitted into your tank and supplied by the hot water returning to the furnace to be reheated after its been through your water to water heat exchanger.

This would still allow you to turn your pole water off and zapp enough heat from the water to reduce the on/off cycling of the furnace. If these heat exchangers are big enough (zap enough heat) then this will be used to warm the tank and allow the heater to run with a reduced number of stop starts. Once the water gets warm enough in the main tank then the heater can be switched off.


 
 

[Spruce]

Steve-sorry, can't insert your quote from my phone

I think it's for for purpose, just think I've possibly used it wrong in that I've used it on demand rather than cycling back into the tank.

What it means is that every time I finish at a house/row, I've got to get back to the van quickly to turn the gate valve so that it cycles

I think that this is the problem. PF sell it as a heat-on-demand heater, but it's not designed for that. It's designed to start up the then run for a long time heating radiators etc on the boat and warming the rooms up before switching off.

The smaller Thermo Top C is also called a block heater. It is fitted into the cooling system of up market cars and 4 x 4's to heat the engine and warm the cabin in freezing weather. It starts and heats up the engine coolant water and once that gets warm it switches on the car's internal fan to defrost the windscreen and warm it up. It will probably run for 30 to 40 minutes before the temperature is reached and the unit will switch off.

The reason why these units go onto reduced heat output at 80+ degrees is that most radiator thermostats to the radiator open in the mid 80 degrees, so its pointless heating the engine higher as that heat will be lost through the radiator.

I have all the kit to put a heater together, but I think the best way is the use the heater to heat the water in to main tank. Maybe another way would be to reduce the size of your main tank and fit a secondary 125 litre tank and use that as the hot water tank. Top it up from the main cold water tank as required.

The downside with using the heater that way is that you need to keep your van frost free during winter. If your heater freezes, than will be an expensive repair, probably replacement.

[Pure Glass]

Thanks Spruce

Just surprised this hasn't been experienced before by others. We know that there are quite a number up and down the country

I'll have to just adapt it I think in order for it to work for me. For a single operator though, that's quite a bit if agg, for a lot of outlay

Oh well

[Spruce]

Thanks Spruce

Just surprised this hasn't been experienced before by others. We know that there are quite a number up and down the country

I'll have to just adapt it I think in order for it to work for me. For a single operator though, that's quite a bit if agg, for a lot of outlay

Oh well

There have been a couple of posts of late highlighting issues.

[Frankybadboy]

not having one of these systems,but looking into getting one.


couldnt you run a simple by pass back in to the tank.so when tap turn of at end of pole.the water continues though bypass back to tank,so heatar is running fulltime then

down side is the pump will be running alot more.but cheaper to replace a pump than the heater bits.

or have i missed something

[Dave Willis]

When I was up in Grimsby they had the recycle option built in then, couple of years ago I think even had the frost stat fitted too. 

[david washbrook]

Mine is a two operator set up but only 1 uses most of the time
On my second real I have the option to leave the pump running and connect the hose to a fitting on the tank which will constantly keep the burner working

So should I always have this connected and running when using the heater and only 1 operator


Steve nice to speak to you the other day glad you got it sorted shame about the cost

[Spruce]

Mine is a two operator set up but only 1 uses most of the time
On my second real I have the option to leave the pump running and connect the hose to a fitting on the tank which will constantly keep the burner working

So should I always have this connected and running when using the heater and only 1 operator


Steve nice to speak to you the other day glad you got it sorted shame about the cost

Do you experience the furnace switching off and then having to restart shortly after? If so then you must do this.

I presume with a 2 man operation you have a 9kva heater.

It would be very helpful to hear from you if your furnace does do this (on/off cycling) and if it does, does having the second operator's system bleeding back to the tank stop it?

The reason for asking is that I have calculated that my 5kva Webasto will keep up with 2 operators even although PF only used to supply that unit for a single operator. I appreciate that they would expect the heater to heat the water much hotter, but they also supply a thermostatic control valve to regulate the temperature output to the brush.

Your heater produces nearly twice the output if it is a 9kva when compared to mine.

[david washbrook]

Spruce yes mine is the 9kw heater and I will chech it tomorrow and post my findings also would it help to have the taps fully open or partically closed I'm talking about the red valves inside the heater unit the ones that allow more or less cold water to mix with the hot ( hope that makes sense)

[Spruce]

Spruce yes mine is the 9kw heater and I will chech it tomorrow and post my findings also would it help to have the taps fully open or partically closed I'm talking about the red valves inside the heater unit the ones that allow more or less cold water to mix with the hot ( hope that makes sense)

Hi David
I would suggest you run it the way you normally would as this would be the way you are most comfortable with. If you turn your mixer valves up, then you will get hotter water which may not be what you want on the glass. Turn the mixer valves down and you will find that the furnace is more likely to cycle on and off more frequently and not give you the results you have come to expect. You don't want to distort your findings.

Try it as a single operator and then as if you had another operator but redirect that hot water to the tank.  If you are experiencing heater cycling issues then it's most likely when you switch your hose tap off as a single operator. If the heater just drops into cruising mode without switching off, that isn't going to cause you any problems.

As per earlier, you put less strain on the heater starter coils if the unit can run almost continously and will use less battery current during the day. (You should also be able to turn the heater off at some point in the day and continue with warm - hot water directly from the tank for the remainder of that day.)

On/off cycles also cause sooting and carboning up in the ignition chamber. Continous running helps to prevent that from occuring and there is the possibility that a good quality diesel could burn some of that carbon off.

Please also consider that if you do opt to bleed the extra heat off with the other system running, then you will need to charge your pump battery more often. It won't be drawing the same current as it would pumping water to the brush head, but it will still be using some current.

Thank you for helping us understand this a little better.

[Pure Glass]

http://m1272.photobucket.com/albumview/albums/PureGlass11/image_zpsfc743596.jpg
http://m1272.photobucket.com/albumview/albums/PureGlass11/image_zpsb4b8479b.jpg

Not sure if the above works, but these show the cycling three way valve and the setup of my heater.

Is there a way I can adapt the three way valve to cycle back to my tank, once my pole tap is turned off? If I leave that gate valve openat the moment, there is insufficient pressure out to the reel, so all i get is a trickle out of the brush head and the heater continues to cycle back to the tank.

If I close that valve (which is how i have been using whilst cleaning), the temperature of the unit increases to 81 degrees and then cuts out and has to start all over again once i turn my pole tap on.

Could i fit a seperate pump on the second heater inlet and cycle that to the tank-would i be able to switch over to my reel?

Thanks again, Steve

[Spruce]

http://m1272.photobucket.com/albumview/albums/PureGlass11/image_zpsfc743596.jpg
http://m1272.photobucket.com/albumview/albums/PureGlass11/image_zpsb4b8479b.jpg

Not sure if the above works, but these show the cycling three way valve and the setup of my heater.

Is there a way I can adapt the three way valve to cycle back to my tank, once my pole tap is turned off? If I leave that gate valve openat the moment, there is insufficient pressure out to the reel, so all i get is a trickle out of the brush head and the heater continues to cycle back to the tank.

If I close that valve (which is how i have been using whilst cleaning), the temperature of the unit increases to 81 degrees and then cuts out and has to start all over again once i turn my pole tap on.

Could i fit a seperate pump on the second heater inlet and cycle that to the tank-would i be able to switch over to my reel?

Thanks again, Steve

Hi Steve,

Pictures don't come up.

A second pump would be the best solution. Most 2 man setups have a pump and controller for each hose reel.

I would look at a 3 bar pressure relief valve on your outlet to hose reel.

http://www.plumbworld.co.uk/pressure-relief-valves-231-0000    page down for example.

I would have preferred to look at 4 bar but with hot water you can use a lower pressure setting on the controllers setup.
If you fit this on the outlet with a t piece then you will always have 3 bar at the brush and when you switch off, the water pressure will open the relief valve and divert that back to the tank. You maybe able to run a higher flow rate so there is always a bleed off occuring.

I would fit a ball valve before the pressure relief valve so you could switch the whole thing off it you just wanted cold.