Eberspacher DW5 Water Heater

[rigger10]

my dw5 water heater has given up on me i fired it up at the beggining of the winter it ran for one hour and shut down , i tried it again and again ,it would not start it will go through the start up procedure but shuts down i have checked fuses the fuel is not pumping the glowplug is not heating up, i have had them seen to and are ok plus the wiring ,the batteries fully charged,alsocut out fuse can you help

 

[pvb]

Welcome to the forums! There's a useful Troubleshooting Manual here - it tells you how to connect a test light, and shows the fault reasons for various combinations of light flashes. Might help you to identify the problem.

 

[jparham]

I presume it runs for 30 seconds or so? may be a minute? then goes through the turn off cycle.
Normally the glow plug uses 16-20 amps for a while before the pump kicks in.
Are you still over 10 volts on the supply to the unit at this current?
Is the relay 'making' to connect the glowpug? I'd start checking there if I had already checked the fuse holder (my problem has always been the fuse holder that gets a dry joint between the fuse and the fuse holder - tends to melt fuses with the heat).
I'd check to see whether the above current is being drawn first. If not, find the glowplug relay and see whether that's switching.

 

[JerryHawkins]

Hi, I assume it is the older D5W and not the later D5WS that you are talking about? The later manuals are also available from the same source as mentioned by PVB.

In any case, these units are essentially very simple - if you have heat, fuel and air they will work. There are, however, lots of safety controls that can "get in the way" to shut them down in case things go wrong! 9 times out of 10 the issue is with the fuel inlet getting blocked with carbon deposits. Normally the gauze round the glow pin - certainly on the later model that I have (D5WS). If you have no fuel AND no heat then there may be a controller fault. If it just the fuel not pumping then it could be the pump. You can easily check this by disconnecting it and arranging to connect it directly to 12v (or 24 if yours is that version). You just need to "flash" the connections across the battery terminals - each connect/disconnect should cause it to "tick" once. If it doesn't tick, then you have found the fault (well, one fault at least!). If it does, then reconnect to the heater and try again.

A strip-down, may well be in order to check all is clean in any case. Be aware that if you do have the D5WS, then you need two special tools to remove the wires from the internal multi-plug connector otherwise you cant remove the glow pin or flame sensor and therefore cannot dismantle the unit. They are about £60 each, but mine have paid for themselves many times over in saved servicing charges.

 

[RAI]

Does the DW5 have an over-heat switch? They usually spring out if the unit looses electrical power without a proper cool down cycle. After that, the heater oil pump will not operate until the over-heat switch is depressed again.