Leaky underground cable

[Tubetec]

I have an oil fired heating system thats in its own seperate boiler house , inside the house by the fuseboard is the timer which originally switched mains power to the burner and hot water pump .
Just lately I've had a fault ,elcb tripped out , I tested the wiring with an insulation tester(1000v range),  3kohms between live and neutral ,11kohms between neutral and ground  . I have already run an auxillary mains supply to keep the heating going , but I have to go out to the boilerhouse to plug in or out  to switch on or off .

Just as a test I  applied 9volts from a cell across my now disconnected neutral and ground wires out to the boiler , sure enough despite the bad insulation 9volts appears at the other end with little or no current draw . 
I'll just provide  +12vdc to the contacts on the timer and down the dodgy cable and use another relay in the boiler house to  switch the  mains supply from a nearby 16 amp outlet.
At 12volts I  can easily afford the 1.2ma of current the poor insulation resistance of the cable costs me , even if the cable degrades further ,it still only consumes a fraction of what the relay does.

I was looking at the wifi theromostatically controlled radiator valve systems  .It comes as a package usually with 5 motorised valves ,I like the idea in some ways ,but I dont  want any of the phone apps or computer based crap , just a simple control panel . Does anyone have experience of these ? 

 

 

[JohnRoberts]

I have an oil fired heating system thats in its own seperate boiler house , inside the house by the fuseboard is the timer which originally switched mains power to the burner and hot water pump .
Just lately I've had a fault ,elcb tripped out , I tested the wiring with an insulation tester(1000v range),  3kohms between live and neutral ,11kohms between neutral and ground  . I have already run an auxillary mains supply to keep the heating going , but I have to go out to the boilerhouse to plug in or out  to switch on or off .

both measurements seem wrong...  In the US neutral should be bonded to safety ground at the service. So 11k is high if still connected , low if open circuit, 3k is also low for what should open circuit when floating. If you are measuring just the disconnected wire those are poor insulation measurements.  At 240VAC 3k is dissipating almost 20W (check my math).  Maybe energize with a few kV and see where it catches fire.

Just as a test I  applied 9volts from a cell across my now disconnected neutral and ground wires out to the boiler , sure enough despite the bad insulation 9volts appears at the other end with little or no current draw . 
I'll just provide  +12vdc to the contacts on the timer and down the dodgy cable and use another relay in the boiler house to  switch the  mains supply from a nearby 16 amp outlet.
At 12volts I  can easily afford the 1.2ma of current the poor insulation resistance of the cable costs me , even if the cable degrades further ,it still only consumes a fraction of what the relay does.

at 12v 3k is 4mA last I checked. Does not seem like a reliable long term fix.

JR

I was looking at the wifi theromostatically controlled radiator valve systems  .It comes as a package usually with 5 motorised valves ,I like the idea in some ways ,but I dont  want any of the phone apps or computer based crap , just a simple control panel . Does anyone have experience of these ? 

 

[Tubetec]

The live and ground wire were isolated from source and load before I did the insulation test ,  I said 11kohms with a test voltage of1000V between what was previously the ground and neutral which was wrong  ,between ground and  live wire was what I meant to say  , so less than 1.2ma current draw at12 volts , of course I dont know what will happen with the leakage resistance  in the future ,
I could call in an electrician and end up paying him , his friend the builder and mate the plumber thousands to dig up the yard to plant a new wire , I think for the cost of a small 12 volt unregulated  psu and a relay or  'contactor' this is worth a shot first .

 

 

[JohnRoberts]

do you have line of sight to and power in the remote  location.

Perhaps a IR controller/receiver pair could wirelessly git er dun...

JR

 

[sodderboy]

Depending on how many zones you have you can get the appropriate (#zones + boiler) TACO relay box, that has it's own 12VDC supply.  Just make sure that the current capability of the relays is at least more than 30% higher than the boiler.  I don't think they draw much but verify that.

I would not use the dodgy wiring.  Get some "direct bury" phone cable from electrical supply, like two twisted pairs or whatever you need.  It has multiple insulations with a layer of silicon goo between them.  I used it to install bullet cams around the property.

And you should really check this out.  An outdoor reset will save on oil by basically separating the pump(s) and the boiler.  I have three zones and as designed when a stat called for heat it fired the boiler and the pump together.  Now with the "outdoor reset" system they are separated.  If one zone just finished heating and another zone calls for heat, it fires the pump and not the boiler because the water is already at 175º.  And it has an outside temp sensor so that if it is 62 º outside it will not fire the boiler to 175º but only 100º or so to heat a zone.  Most new boiler systems include a built-in outdoor reset.

The two huge benefits are 20-25% oil savings and much more even temps in all zones.  I installed it pretty easily and it paid for itself in less than one season.  I can post the schematics that Tekmar does not include in the current rev of the installation manual.  I think that boiler techs complained to Tekmar that it was too easy for crafty homeowners to install and they removed the schemos.

 

[Tubetec]

I found a 16A single pole relay with a 12 volt coil , I mounted that up in a din box in the boilerhouse switching the new incoming  live terminal. In the house I rigged up  an unregulated 9V dc 250 ma supply from an amputee  wall wart screwed down to a piece of timber , I added a fuse holder in the output cable which doubles as a circuit break-in to patch a multimeter for current draw measurement . As a baseline I measured the draw on the relay alone to be 31ma at 9v , 
Dc on load voltage from the supply is 11.9v I measure a total current of 44ma  ,so yeah  I can live with the loss of  a few ma . Everything works great now again .

In relation to the thermo controlled motorised radiator valves ,there is a non networked option , it has its own  timer/temp sensor and  operates standalone  ,programable ,with a boost button for instant heat , requires two aa batteries ,  they cost between 10-20 euros for the basic un-networked version , networked versions go up to around 50 ,some bluetooth some wifi and some dect . It seems you can make better use of boiler time and create heat zones relating to which rooms you use at which times of day . Also should serve to better balance outputs between rooms .

This system is single pump/single zone  with water temp at the boiler  controling on and off  , it should automatically react when  TCV's control the demand to various rooms .
Allowing outside temp  be the trigger for 'system on' makes plenty of sense but I can be fairly certain  around 6 months of the year I dont need heating at all , if there is the odd cold day I need it I can trigger it to come on if and when needed.  The controller does incorporate an automatic freeze sensor , where in the event of a low temp the system fires up regardless.

 

[sodderboy]

An outdoor oil burner seems quite old fashioned.  Is it just outside the house?  Can you post a pic?  If you are in a cold zone, it will consume more oil keeping itself alive than keeping you warm.

Mike

 

[JohnRoberts]

An outdoor oil burner seems quite old fashioned.  Is it just outside the house?  Can you post a pic?  If you are in a cold zone, it will consume more oil keeping itself alive than keeping you warm.

Mike

It may be a conversion of an old school wood/peat fired heater, that was located away from the living space for good reasons. Modern oil burning heaters run much cleaner.

My old neighbor across the street (now RIP) had a wood burning heater located in a free standing building/shed away from his house.  Several years before he died he lacked the energy to feed wood into it, at dark o'clock in the morning, and sold it.

JR

 

[Tubetec]

Just to finish things off I moved the timer switch to the primary side of the psu  , only energising the transformer when required saves the watt or two of heat dissipated by the core, in use the relay consumes a few hundred milliwatts and the leaky cable consumes maybe 10's of  milliwatts .

 

[JohnRoberts]

sounds good for now, if it stops working you will know soon enough.

JR

 

[Tubetec]

I gave the boiler a full service  a month or two back ,it is old but its still running great  .Oil fired heating is still the predominant form of home heating in rural Ireland . Even in winter here I dont usually need to heat during the daytime , at night and early in the morning I run it for a few hours.

Next problem is phone line doesnt have the usual 50 or so volts across it anymore , broadband connection still works down the same wires  . Im suspecting poor insulation out at the telegraph pole, I have of course disconnected the phones inside the house to discount a fault there , definately a problem on their side .Its been a nightmare trying to get to the proper customer service section .

I knew when the first two electrical issues hit me ,likelyhood was a third curve ball was coming my direction ,sure enough when I went to finally unpack and  install a cooker delivered almost 1 year ago to the day , the glass door of the main oven was shattered to 1000 pieces. Definately happened 'in transit' as I saw it being delivered carefully , not sure how I stand with insurance its been so long. I need to call to see the store manager tomorrow . 

So yeah several Headf%*^$ in a row  ;D but thats how it goes .

 

[sodderboy]

Bend with the wind. . .