Hi,

I bought a tankless waterheater to replace one waterheater with tank. The original breaker was 30 amp and the tankless requires 60 amp breaker and No. 6 gauge wire.

My question is if I do not change the breaker and wire, what adverse effect it may have on the water heater itself?

The symptom I saw was that it heats up water all right, the breaker did not trip, but the heating elements was always on. The heating elements supposed to be off when the flow was stopped.

Appreciate your help. Thanks.

You have to change the breaker and the wire. The tankless heater draws much more current and that is why you need the larger wire. The breaker is replaced because of the same high current draw of the heater and the load that will be imposed upon the wire. Do it correctly. Follow the directions that came with the heater exactly.

I have asked to have this moved to plumbing. We have some people there that have experience installing them. The low voltage from undersized wires may have caused the contacts to heat up and weld. I would leave the breaker off until you get some answers.

H&A/C is the best forum for anything with fire.

I'm going to leave the post here. This question also falls under, HVAC, electrical and plumbing.

If there is too much voltage drop along the under sized wire, the amp draw will go up, causing damage to the unit and elements like Labman stated. But more so, it is a hugh fire hazard since the wire could overheat and start the insulation on fire before the breaker trips, please do it the way the manufacturer suggested.

Hi,

I bought a tankless waterheater to replace one waterheater with tank. The original breaker was 30 amp and the tankless requires 60 amp breaker and No. 6 gauge wire.

My question is if I do not change the breaker and wire, what adverse effect it may have on the water heater itself?

The symtom I saw was that it heats up water alright, the breaker did not trip, but the heating elements was always on. The heating elements supposed to be off when the flow was stopped.

Appreciate your help. Thanks.


This question is FIVE YEARS OLD and it came up with a search for new question for the LAST WEEK!! Something needs to be done to purge these old questions.

This question is FIVE YEARS OLD and it came up with a search for new question for the LAST WEEK!!!!!!! Something needs to be done to purge these old questions.

If anyone uses the search feature they might just find there problem has been discussed by an earlier post. I can also understand the frustration with the older posts or the people who post to older posts for help and no one will answer since it is a old post. Thanks for helping out Handyman2007.