Water temperature sender part number?

[paddler1]

Would anyone be able to inform me of the part number for a BMC1500 water temperature sender please? 

[Tony Brooks]

13 minutes ago, paddler1 said:

Would anyone be able to inform me of the part number for a BMC1500 water temperature sender please? 

 

For that we need to know the make of gauge and model number. It could be built to US or European standards and if you mix them the gauge either reads about twice or half of what it should. If it is a genuine BMC sender it is probably the European standard and the ASAP supplies list a lot of senders. Also measure the threaded part diameter and if you can how many threads per inch.

[springy]

It probably depends on the brand of the gauge - IIRC European and American manufacturers use different designs and using the wrong one will give inaccurate readings.

 

springy 

 

beaten to it by Tony

Edited March 2, 2022 by springy

[paddler1]

This is good news indeed so thank you both!

i had my CH refurbished and I think a new sender was added so it probably doesn’t match the gauge then now according to what u say as its worryingly showing to be 120 degrees after only ten minutes on tick over. However, I can feel the top of the heat exchanger is no where near that temperature! 

[Tony Brooks]

FWIW ASAP's website used to and may still give the resistance of their temperature senders so you can work out which standard they are120 sounds like Fahrenheit to me, and that sort of implies a US gauge.

 

If it were a straight gauge-sender mismatch then 120C would be roughly a true 60C and it does not sound as if your engine is at anything like that. However 120 is till incorrect. Is this full scale deflection on the gauge? If so the gauge sender or earth wire may have fallen off. That is assuming a bi-coil gauge. It also occurs to me that some very old boats (60s & 70s) may have thermal gauges and most of  those need a voltage stabilizer in circuit. If that fails then you either get no reading or full scale deflection immediately. If it is a Smiths gauge this might be the fault.

 

Makers name on gauge?

Marked in C or F?

How many terminals on the back (ignoring any for illuminating lights)?

Is 120 full scale deflection?

Will all help to give better advice.

[paddler1]

It’s a Faria gauge showing C and F with just 2 wires connected to it.

hope these photos help?

[Jen-in-Wellies]

The gauge appears identical to this one.

https://www.asap-supplies.com/products/faria-beede-water-temperature-gauge-in-euro-black-style-euro-resist-far12814

Which uses a European resistance sender.

They do make one that uses an American sender, but that has Fahrenheit as the major scale and Centigrade as the minor one. https://www.asap-supplies.com/products/faria-beede-water-temperature-gauge-in-euro-black-style-us-resist-far12812

 

[Tony Brooks]

Whoever wired it is a prat. It is a bi-coil gauge and needs 3  wires. Plus minus (ground) and sender. Your ground cable is missing so you get all but full scale deflection. As the sender is fitted into an adapter  think the sender and gauge are matched. i would check the other two cables are on the correct terminals.

[Rincewind]

It would appear that the neg terminal for the gauge is also common to the neg terminal for the lamp  (copper / brass strip seems to suggest both are connected); is there a negative wire for the lamp, somewhere behind the panel, that has come adrift? (A Faston Connector)

Edited March 3, 2022 by Rincewind

[Tony Brooks]

21 minutes ago, Rincewind said:

It would appear that the neg terminal for the gauge is also common to the neg terminal for the lamp  (copper / brass strip seems to suggest both are connected); is there a negative wire for the lamp, somewhere behind the panel, that has come adrift? (A Faston Connector)

 

Brass  strip - yes, looks like a common negative.

 

Negative wire for the lamp, probably no because you don't have  a lamp positive and most narrow boats don't use instrument illumination.

 

Negative wire for gauge operation - how the hell should we know. We know there should be one but it is not in sight so it is not there for a reason like the old gauge did not need it (bi-metalic type), the fitter disconnected it and lost it, the fitter did not know what he was doing and cut it off. You need to get behind the panel and start looking OR fit another one connected to any available negative terminal.

[Tracy D'arth]

Easiest and most sure fire is to replace the sender and gauge with a new matched pair.

[Tony Brooks]

Just now, Tracy D'arth said:

Easiest and most sure fire is to replace the sender and gauge with a new matched pair.

But not until the OP has the full compliment of necessary cables. I think from what I can see it was replaced as a pair but a wire was left off/out.

[David Mack]

3 hours ago, Tony Brooks said:

Whoever wired it is a prat. It is a bi-coil gauge and needs 3  wires. Plus minus (ground) and sender. Your ground cable is missing so you get all but full scale deflection. As the sender is fitted into an adapter  think the sender and gauge are matched. i would check the other two cables are on the correct terminals.

Installation instructions, from https://www.google.com/url?sa=t&source=web&rct=j&url=https://fariabeede.com/site_manuals/IS0002_F.pdf&ved=2ahUKEwim2Kui36r2AhUXSEEAHTXQCcQQFnoECB8QAQ&usg=AOvVaw3GkHy5J332oWxAzXyk7rQK

[Rincewind]

1 hour ago, Tony Brooks said:

 

Brass  strip - yes, looks like a common negative.

 

Negative wire for the lamp, probably no because you don't have  a lamp positive and most narrow boats don't use instrument illumination.

 

Negative wire for gauge operation - how the hell should we know. We know there should be one but it is not in sight so it is not there for a reason like the old gauge did not need it (bi-metalic type), the fitter disconnected it and lost it, the fitter did not know what he was doing and cut it off. You need to get behind the panel and start looking OR fit another one connected to any available negative terminal.

I was not suggesting that the Lamp was connected at some point to provide illumination, I was suggesting that the person who fitted the gauge saw the opportunity to use a "faston" connector to make the neg connection, rather than use a ring connector on the gauge terminal, - (who is to say that the gauge fitter also fitted the ring terminals on the two cables that we can see and / or had spare ring terminals in his pocket?), - and that the female "faston" wire connector may have become detached (for whatever reason) from the male connector on the gauge body, hence the my inference that there may and I repeat, MAY be a negative wire that terminates in a "faston" connector "waving about in space" behind the panel.

 

"We" do not know if that is the case or not until the OP investigates, which is why I suggested, (by means of a question mark), that this possibility would be a good next step for the OP to follow, i.e. look behind the panel for loose / unconnected wires! 

 

The OP should, in my opinion, be encouraged to investigate looking behind the panel in any event.  Now that this possibility has been raised, in that a negative wire could be waving about in space behind the panel, it is not good practice to ignore it. (if it is there at all, and in this point in time we simply do not know).  A loose negative wire that could come into contact with an uninsulated positive terminal (and there is one on the gauge itself) is just as bad as a positive wire waving about in space that could fall onto a negative terminal.

 

I  am not implying that the gauge fitter is a Saint - and he may well turn out to be the Devil himself - but is it proper to crucify him at this stage without knowing the full facts - which we do not.

[paddler1]

I have taken off the panel but there does not seem to be any ‘spare’ loose wires that would have gone to the back of this gauge. 

I will have a closer look in the daylight tomorrow.

I appreciate the information so far although even though you say there may be a wire missing  on back of the gauge it was working perfectly well before the CH was taken off which mystifies me? I also spoke to the engineer who has now told me that he did not replace the sender so both the sender and the gauge remain the same that previously worked.

 

[Tony Brooks]

20 minutes ago, Rincewind said:

I was not suggesting that the Lamp was connected at some point to provide illumination, I was suggesting that the person who fitted the gauge saw the opportunity to use a "faston" connector to make the neg connection, rather than use a ring connector on the gauge terminal, - (who is to say that the gauge fitter also fitted the ring terminals on the two cables that we can see and / or had spare ring terminals in his pocket?), - and that the female "faston" wire connector may have become detached (for whatever reason) from the male connector on the gauge body, hence the my inference that there may and I repeat, MAY be a negative wire that terminates in a "faston" connector "waving about in space" behind the panel.

 

"We" do not know if that is the case or not until the OP investigates, which is why I suggested, (by means of a question mark), that this possibility would be a good next step for the OP to follow, i.e. look behind the panel for loose / unconnected wires! 

 

The OP should, in my opinion, be encouraged to investigate looking behind the panel in any event.  Now that this possibility has been raised, in that a negative wire could be waving about in space behind the panel, it is not good practice to ignore it. (if it is there at all, and in this point in time we simply do not know).  A loose negative wire that could come into contact with an uninsulated positive terminal (and there is one on the gauge itself) is just as bad as a positive wire waving about in space that could fall onto a negative terminal.

 

I  am not implying that the gauge fitter is a Saint - and he may well turn out to be the Devil himself - but is it proper to crucify him at this stage without knowing the full facts - which we do not.

 

As I can only see two cables, probably the pos. and gauge wires, I don't know where you get a negative faston connection from. The thing that looks like a 9mm Lucar female blade is probably the illuminating lamp positive and if a negatve is connected there it will put the bulb in series with the compensating coil so the gauge will still read incorrectly. Also the fitting instructions show the negative is intended to go to the stud.

 

I come back to the fact that bi-coil gauges need three wires and they will not work correctly with just two. The manufacturer's instructions confirm this. Anyone expecting paying for work done should know this and should thus have ensured there were three wires connected.  If it was working properly before the OP had the work done it must follow that whoever did the work managed to lose the negative wire in one way or another.

 

It could easily have been looped from a nearby negative on another gauge or illuminating lamp and if it was just a blade connection it could easily have been knocked off and lost. It is even possible that the missing wire has been cut off at the loom and taped over or has pulled out of a poorly crimped eye terminal.

 

As for saint or devil anyone who tales money for work done and makes fundamental mistakes, quiet apart from not doing adequate testing is either an idiot or a fraudster. Regrettably both are all too common with inland  boat "professionals".

 

We both agree that the OP needs to look for that negative cable and if not found make one up and connect it.

[paddler1]

Ok, so I have had a good look behind the panel as recommended and taken a few photos to help.

Definitely only 2 wires to the gauge with none apparently ‘lost or missing’.

purple wire goes to ‘s’ and red to ‘i’ with the middle nut screwed down tight marked ‘GND’ which I presume is the ‘ground’ that Tony spoke about.

 

next to it is the oil pressure gauge.

 

one brown wire from the sender. 

 

 

[Tony Brooks]

The second form bottom photo shows what looks like a negative bus bar the "strip" with all the black wires connected to it. If that is negative then run a wire from that to the GND terminal on your gauge. Test the bus bar with a voltmeter. First between it and battery positive, it should give battery voltage. Then between the bus bar and ant clean metal on the hull, engine or battery negative. it should red zero volts.

 

I note the gauge beside it that I think you said was an oil pressure gauge also seem to be wired in a very odd way for a bi-coil instrument in that it also only has two wires on it and assuming black = negative  (by no means certain) then it has no sender wire. In one image it also seems to have the negative and what might be the sender wire on the same terminal. That has to be wrong and I doubt that gauge is working properly either.

 

I am sure they are bi-coil gauges because of the three connections and the wirirng diagram someone posted.  All bi-coil pressure, temperature, and level gauges have the same insides and are wired the same.

 

[Jen-in-Wellies]

Tony just replied with what I was going to say. Also, what is the gauge in the top left of the first picture and who is the manufacturer?

The ground bus bar @Tony Brooks is talking about is shown below. Looking at the number of old screw holes in the wall, there has been a lot of electrical modifications made over the years.

[Tony Brooks]

More info, but I very much doubt it is relevant here. There is another gauge technology called air core. On these when you turn the electricity off they tend to stay where they think they will aka many rev counters. They only lead true when a current is supplied. I am not 100% up on those but I don't for a minute think I have ever seen a marine gauge like this apart from rev counters. They MIGHT only need a two wire connection but if so they have to be paired with a stabilized supply, otherwise they still need two coils and three wires.

 

Explanation of bi-coil gauges in the electrical notes on my website.

Edited March 4, 2022 by Tony Brooks

[paddler1]

Here is an update by way of a thank you too.

Added the additional wire as instructed and had a test sail today following my CH renovation.

It went well and the temperature was accurate and stayed mid way around 80c which I think is about normal so it looks like I have no air in the system either.

My only query now is following up from what Tony wrote that maybe I need to address the oil pressure gauge - do I need to put a wire to that too from the negative buzz bar? To be honest, Iv never paid  much attention to this gauge...probably wrongly but what should it read as it usually goes up to about 100psi?

Thanks all for your time and content.

 

[Tracy D'arth]

4 minutes ago, paddler1 said:

Here is an update by way of a thank you too.

Added the additional wire as instructed and had a test sail today following my CH renovation.

It went well and the temperature was accurate and stayed mid way around 80c which I think is about normal so it looks like I have no air in the system either.

My only query now is following up from what Tony wrote that maybe I need to address the oil pressure gauge - do I need to put a wire to that too from the negative buzz bar? To be honest, Iv never paid  much attention to this gauge...probably wrongly but what should it read as it usually goes up to about 100psi?

Thanks all for your time and content.

 

Not many engines run at anything like 100psi, I suspect that gauge has the same problem.  40 to 50 psi would sound better.

[Tonka]

On 03/03/2022 at 17:32, Tony Brooks said:

 

Brass  strip - yes, looks like a common negative.

 

Negative wire for the lamp, probably no because you don't have  a lamp positive and most narrow boats don't use instrument illumination.

 

Negative wire for gauge operation - how the hell should we know. We know there should be one but it is not in sight so it is not there for a reason like the old gauge did not need it (bi-metalic type), the fitter disconnected it and lost it, the fitter did not know what he was doing and cut it off. You need to get behind the panel and start looking OR fit another one connected to any available negative terminal.

Beta panel has illuminated panels. Mine definitely does and I replace the bulbs when they blow

[Tony Brooks]

18 minutes ago, paddler1 said:

Here is an update by way of a thank you too.

Added the additional wire as instructed and had a test sail today following my CH renovation.

It went well and the temperature was accurate and stayed mid way around 80c which I think is about normal so it looks like I have no air in the system either.

My only query now is following up from what Tony wrote that maybe I need to address the oil pressure gauge - do I need to put a wire to that too from the negative buzz bar? To be honest, Iv never paid  much attention to this gauge...probably wrongly but what should it read as it usually goes up to about 100psi?

Thanks all for your time and content.

 

 

I bet 100 psi is getting on for full scale deflection. Yes add a negative cable.  I bet it will then run between about 40 and 60psi.

[Jen-in-Wellies]

49 minutes ago, Tony Brooks said:

 

I bet 100 psi is getting on for full scale deflection. Yes add a negative cable.  I bet it will then run between about 40 and 60psi.

Further, The pressure will drop a bit running as the oil warms up over half an hour or so and its viscosity drops. Entirely normal, so 50 to 60psi cold, dropping to maybe 40psi, for a happy engine. The oil warms up at a slower rate than the coolant.