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Improving Indirect Hot Water System?

We have a three-year-old, Superstor-45 indirect hot water system connected to our natural gas boiler. The problem is that the hot water tank must have priority over the remaining four heating zones. During times of heavy hot water use such as when we have overnight guests, the circulator to the hot water tank is often running, therefore, we can't heat our home for several hours at a time as no zone may run until the hot water system shuts off.. This is a problem in winter and we sometimes lose several degrees of house temperature.

I'm thinking of adding a tankless hot water system to use as a pre-heater, feeding hot water into the indirect tank. This should greatly shorten the running time of the indirect hot water tank, allowing our heating zones to function more efficiently and to better respond to their respective thermostats.

I would appreciate any thoughts or suggestions on how I can overcome the problem I describe.

Re: Improving Indirect Hot Water System?

At this point, I would say that thinking about adding a supplemental tankless hw heater is the LAST thing that should be on your mind---there are a number of much less expensive options that you have to check out with the idea that this problem should be able to be easily solved by making a few minor adjustments to the equipment you already have-----in my opinion, you shouldn't have to buy any additional equipment to resolve this problem.

If you haven't done so already, contact at least 2 or 3 heating service contractors in your area (start with your regular service person) to see if they can make any one of several minor adjustments to the indirect HWH & the boiler controls that will give you the amount of dhw (domestic hot water) that you need & at the same time, will provide adequate heat for the various other zones of the house.

Have you had any service person over recently to explain to them the problem you're having??? if so, what have they said about what your options are???----for example, sometimes it helps if the dhw (superstor) is simply taken off priority mode; what is the "high temp" control (gauge) on the boiler set at???----if it's now set at approx 160-170 degrees, it can be simply raised to 180-200 degrees to keep the boiler water much hotter, & thus considerably shorten the time the circulators have to run to satisfy the needs of the superstor, or the various other house zones.

The recovery rate & the gallon capacity of the superstor indirects should be enough to keep the house in an adequate supply of domestic hot water---however, another possibility is that the boiler itself is underfired & may need a larger capacity gas valve to provide more heating punch ( a relatively low-cost, minor adjustment).

The boiler itself may be too small, or too old to provide the tens of thousands of btu/hr to adequately heat the dhw & the house zones.

Re: Improving Indirect Hot Water System?

Many thanks for your response. No, I haven't yet had a service man, actually, a licensed plumber, in to assess the situation. I thought I'd bone up on my options before making an expensive mistake. I keep the boiler set at 190 degrees and it is a Slant Fin, installed approximately 20-25 years ago.

Incidentally, during Hurricane Sandy, we had 10 inches of water in the basement but it did not reach any of the electronics. I did not note any apparent damage to the heating system.

Re: Improving Indirect Hot Water System?

You might wanna head on over to the Terry Love Plumbing forum or wait until Maurice shows up.

He's old and naps a lot.

Well deserved naps they are. :cool:

Re: Improving Indirect Hot Water System?


I agree with brewster.

You need an experienced, knowledgeable heating service contractor (not necessarily a licensed plumber) trained in hydronic (hot water) heating systems (check the Yellow Pages display ads under "Heating Contractors") to actually show up in your boiler room to assess the problem; if the contractor by some chance can't find the solution to the problem, or suggests you call someone else in the area who is more experienced in hydronic systems, the charge for the service call should be zero.

The service call is not going to cost you anywhere near an "expensive mistake" amount (especially not for an off-the-wall idea of spending thousands for a supplemental tankless heating system), and part of the learning curve on YOUR part is to go thru this process so that you can eventually line up one or two pros in your area that are knowledgeable in hot water heating systems, & you can rely on when problems like this periodically occur with the heating system to respond promptly, fix the problem, & charge a reasonable rate (or nothing at all if they don't fix anything) for the repair.

Do your research; call every relative, friend, & co-worker you can think of (especially those who have HW heat) until you get the names of several heating techs in your area that service HW heating systems & that your close contacts say do a good job at a reasonable rate.

You've got to do some networking here; also ask your relatives, friends & co-workers if they belong to any contractor review services like Angie's list (or join yourself for a few $$) & ask them to look up recent reviews/ratings of local heating service techs in your area for those who have scored high on customer satisfaction reviews.

Some contractors will suggest taking out a service contract to cover periodic repairs like this, but this is completely at YOUR discretion & would be based on the level of satisfaction that you had with the work done, the attitude (positive or negative) of the service person & the fee charged for the service visit.

In addition, most hydronic service contractors welcome homeowners to closely watch the work being done & will work with the homeowner (this seems to be especially true of homeowners who have HW heating systems) to show them what went wrong & suggest ways that THE HOMEOWNER CAN MAKE MINOR REPAIRS/ADJUSTMENTS THEMSELVES in the near future if the same problem recurs.

Re: Improving Indirect Hot Water System?

We've got some very knowledgable Senior Members on the forums whose advice and experience is well worth waiting for. Not bashing anyone else, but these guys have a proven track record and I trust who and what I know more that what and who I don't. This is not my area of expertise but even I can see that 'adjustments' alone may not do you much good if the system isn't properly sized and you're asking more of it than it can deliver.

You need good advice wherever the source- be sure you're getting that before you start spending money ;)


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