Why did transformer on L8148E go bad?

Joseph_4

I have a customer who has had an L8148E triple aquastat, whose transformer was used to power 2  Honeywell V8043 zone valves. It powers an electronic ignition module and gas valve as well. The system gave no problem for 25 years. The transformer now burnt out. (nothing has been changed in the 25 years) The literature from honeywell says it can handle 2 zone valves, but that is the max.  1) why did it burn out now 2) would you install  a separate transformer for the zone valves at an added cost to customer or install only a new L8148E and hook up zone valves as they have been for 25 years?

Thanks

Joe

icesailor

Transformers going bad:

Can you imagine? My POS 2000 Ford van, that I bought new, with 97,000 miles just needed the exhaust system replaced? How long should it last?

And at 90,000 miles I had to replace the plugs and ignition wire caps?

25 years on a transformer? How long do you think it should last? How efficient is a 25 year old boiler, that wasn't all that efficient when it was new?

Replace the control. Nothing lasts forever. I'd also add the other transformer. Maybe the ZV's are drawing extra load after 25 years and you could use a bigger transformer. Just because it says it will take 2 zone valves, means that it will comfortably. With Taco 57* zone valves, a 40 VA transformer will operate 3 valves. You can connect 4 valves but it will only open any 3 at a time.

Joseph_4

Does a zone valve pull more VA with age?

Is it true that a zone valve pulls more VA with age. For that matter does a gas valve pull more VA with age? 

Tim McElwain

Take an

amperage reading of each one of the load controls total it up and multiply it times the voltage reading this will give you the total VA (wattage) draw on the transformer. The L8148E will have a 40 VA (watts) transformer if it has a TV and Z connection. That should be able to handle 3 Taco ZV's or 5 Honeywell ZV's as Taco draws around 1 amp and Honeywell ZV's draw about .2 amps. If the transformer is a NEMA (National Electric Manufacturers Assoc) rated standard DC20-92 transformer it can handle almost 200% of its capacity with just a small drop in voltage.



All electrical components as they age will tend to draw more current as there resistance increases with age. With coils we are not however dealing with a pure resistive circuit but with Inductive Reactance.The problem is voltage remains constant in most cases and resistance increases so if you do the math less current is available



I would go ahead and change the relay, by the way you can use an L8148J Universal Replacement relay.