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Posted by Doug on June 21, 2007, 4:09 am
On Wed, 20 Jun 2007 12:40:34 -0700, Paul Flansburg
>> I bought a house last year that has a Weil-McLain boiler/tankless
>> heater. I believe it was installed in 1992. It looks pretty beat
>> up---more rust and the like than I would expect on a boiler that's
>> about 15 years old---but I'm told that the water around here is pretty
>> hard and that it eats up boiler. (On the other hand, I have a water
>> softener system, so what's that all about?)
>>
>> Anyway, the boiler simply doesn't provide enough hot water. We can't
>> fill up the bathtub, and showers get cool after a short period of
>> time. Even when the boiler kicks back on, the water only becomes
>> warm, not hot. I can deal with this in the shower, but I'm concerned
>> about the washing machine and dishwasher.
>>
>> The heater part of the boiler has three controls as far as I can
>> tell. There are two thermostat controls that determine when the
>> boiler fires on and off, and a valve that blends the hot water from
>> the heater with cold water to deliver to hot water faucets.
>>
>> If I want more hot water, how should I adjust these things to serve us
>> better?
>>
>> Also, I read on the Weil-McLain web site about an indirect-fired water
>> heater. Is this something that adds onto a tankless system to provide
>> extra hot water? (I have no idea if this could physically fit into
>> our mechanicals closet, but it's somethng to look at if it would take
>> care of the problem we are having.)
>>
>> Any suggestions appreciated!
>>
>> Thanks,
>> -Ben
>
>Ben,
>
>First, Don't touch the setings for the hi and low limit. They are the
>dials on the primary controller. Typically it's a Honeywell. The
>settings(typically) should be around 180 for the hi and 160 for the
>low. Leave the other dial for the differential at 20. Lets start
>here!
>
>Okay, now to fill a bath tube with water is going to use up a lot of
>hot water. The typical tankless is about five gallons. YOur boiler
>should be firing during this time. It may cycle a few times, but for
>the most part it should be firing. Anyways, since you mentioned hard
>water you may have two problems. The tankless coils could be caked
>with scale and or the mixing valve could be fried. Have you tried to
>incease the level of hot water? If the dial is maxed out then you may
>want to start with this. Do you have any plumbing skills? Start with
>the smaller and cheaper parts before doing anything to the boiler. I'd
>replace the mixing value first.
>
>You mentioned indirect hot water. This is your next option. I say
>this because replcing the tankless is almost next to impossible. Most
>of the time the a stud or several tend to break cause more of a
>problem. If the tankless is not leaking I'd leave it be. You can add
>a booster/holding tank onto the tankless. Let the tankless heat the
>water and store it in a 40 or 50 gallon tnak. The indirect is tied
>into the boiler as another zone and will require additional
>electronics to turn on the circulator for heating the water.
>
>Another good site to check is heatinghelp.com. Lots of resources
>there.
>
>-paul
I'd agree with the above except that a tankless coil CAN be replaced.
Many boilers about the age of your Weil-McClain and newer have used
stainless bolts to fasten the tankless coil. In any event, with some
caution, time and penetrating oil, I've removed tankless coils. A
replacement coil is only about $150 plus labor if you don't do it
yourself.
The tankless coil is simply a copper coil submerged into the boiler
water. Typical output flows from a tankless coil is about 2.5 to 5
Gallons Per Minute. That's up to 5 GPM of VERY hot water. Thus the
mixing or tempering valve is often used to reduce the likelihood of
scalding.
Another treatment for a "limed up" tankless coil is to flow
hydrochloric acid through it. I've done it myself and fumed up the
basement quite a bit so it has to be done with plenty of ventilation
and extremem caution, with protective rubber gloves, etc. It was quite
successful and restored the hot water output flowly to normal. Most of
the younger techs in the HVAC world won't do the acid cleaning. Most
old timers will.
An indirect water heater is an option. As the poster above states, it
runs as a seperate "zone" off of the boiler. However, such an
installation is fairly expensive and will consume a good amount of
space in your utility room. An indirect water heater will take up
nearly as much space as your boiler.
Doug
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