Please advice on Garn distribution system

[Scott from Canada]

[quote author="Scott from Canada" date="1261038484"]Hello all, I took the Garn plunge. We made the 18hr round trip and hauled the unit home about a week ago.The day after we got back I had to go in for some surgery(lifted something I should not have a few months ago) so unfortunately all I have been able to do is read the manuals and look out the window at that shiny new 1500.Thank you all that have helped me make the decision to purchase what looks to be a solid, serious piece of heating equipement. Hopefully I can get some more assistance from the resident expert's on the forum to help me further my distribution design along while I am recovering. Scott[/quote]

Hello all,
I took a shot at laying my distribution system out.I tried to apply what I have learned from the experts on the forum.I was hoping I could get you guys that have the experience have a look at my plan and advice me on any changes you would recommend.I know everone is busy at this time of the year.I'm going to be recovering from surgery for a while so when ever you guys find time would be much appreciated. I will only be able to try and get the shop heat going this winter as I did not get the pipe in the ground to the house before the grund froze solid.
All feedback is welcome. Thanks, Scott

 

[Sawyer]

Hi Scott,

It has to feel good to have the Garn home before winter storms arrive.

Will the shop be forced air heat via coil if you are only doing the shop for this winter? If so you should not need a HX or mixing valve at this time as your coil will want max heat.

You would need a HX at the furnace coil if you are connecting to an existing closed hydronic system.

A mixing valve will be needed if you go to in-floor/radiant heat. I have a mixing valve on my DHW outlet to temper the water to the faucets for scald protection.

The Garn does not require a pressure tank.

BTW, 90K btu/hr seems high to me. Did you run a heat loss calculation? My 1200 sq/ft shop with 11’ ceiling is only 36K.

You may do better designing your system for your future needs once you bury the supply to your house now and then tap into those fittings later rather than doing a temporary system just for the winter. I hope this gives you a little food for thought. I am sure others that are much more experienced will chime in shortly.

 

[Scott from Canada]

Sawyer thanks for your feedback. Yes you are correct it is good to have it home. My brother and I went do to get it to save a little cash on shipping and we really lucked out . We had perfect driving conditions and no breakdowns.The heat loads were all calculated some time ago. I think it is higher than you expect because it is an arch rib design, 15' ceiling, and for design purposes it was based on -40F temp worse case. Yes I do need to add a mixing valve at the DHW and at the floor heat. You are also correct on the HX at the DHW tank thanks. I put a question mark on the Plate HX and mixing valve because I have seen both system configurations used on the forum. Same goes for the pressure tank.Just thought I would throw it out there for comment. I thought I would show the entire preliminary design out there because I am sure all loads and flows will be required to size pumps, piping etc.I am hoping more will chime in and offer their expertise as you did so I can tweak the design so that when I can start the install with the shop end I will be sizing and configuring everything correctly.To tell you the truth I have looked over charts for pipe sizing, pump sizing and head loss and I am a tad over my head.So I am relying on the good folks that have the experience to help. Thanks much, keep the comments coming. Scott

By the way your setup, yard, and house look impressive.

 

[Sawyer]

Hi Scott,

Perhaps someone with a design program will have time to run you system design loads on their design program and give you the sizing information from the report.

I am heading to Menards for more insulation in a minute. Good luck with your install.

Happy Holidays,

George

 

[Jim K in PA]

Scott,

That is quite a plethora of loads you have to plan for. I and others will certainly give you whatever feedback we can, but you should probably consider hiring someone to do some ME design work for you. Talk to the folks at Dectra. They do design work for a fee, and certainly know their stuff.

Having said that, your layout prompts a number of questions. Your first goal is to decide how to route the piping to the house and the pool. You also need to get a handle on the total forseeable loads so you size your piping properly.

Does your 70k Btuh house load include all the components you list? (BB, RF, Towel bar(!), and future loads? If so, it looks like you will need at least 1" lines, and perhaps 1.25" lines underground to the house.

What is your DHW load? If that is not included in the 70k Btuh figure, you need to add that load to the total so the piping and pumps get sized correctly.

If you have to pipe the water to the pool in the summer through the lines to the house, then you might want to consider going to 1.5" lines underground. Can you run a seperate line to the pool directly from the GARN so you can drain them for the winter?

Set up an HX in the house, and then you leave your pressurized house piping mostly intact. An expansion tank should already be part of your house piping. No tank needed for the GARN side, since it is not pressurized.

The shop is the easy part - put in some closely spaced Tees in the supply line and feed the hottest water you have to the fan coil.

With the total max forseeable loads approaching 200k Btuh (shop+house+DHW), I am surprised your dealer did not recommend going with a WHS2000. If you actually see these full loads, you will be burning every 3-4 hours just to keep up. A 2000 would give you a couple more hours. Hopefully these numbers are very conservative, and you will not see such loads often, if at all.

 

[Scott from Canada]

Jim, thanks for the feedback.Perhaps I am using the wrong wording when I refer to the house and shop 'loads'. Those BTU/hr figures are what I arrived at when I ran the building data through heat loss calculator using worst case scenario -40C or -40F temps, for design purposes. I may still need to provide GPM through the furnace coil requirement and total BBH gallon/min for example for design purposes? The existing hot water tank is an electric 60 gal. I'm not sure how to translate that into BTU/requirement or GPM required. Perhaps I need to have the HX for the sidearm sized first, t hen get the GPM from it. The basic plan was run by the Garn rep. and he did suggest going with a 2000 but said a 1500 would do.He stated the same as you that I would be looking at 1-2 hours less time between burns.A 2000 would be better but I am on a tight budget so I had to go with the 1500 or nothing. The plan is to place the Garn in the shop trench insulated pex to the house then take off out of the house to the pool shack where the pool HX would be. I was hoping to drain the pool lines for winter, as you mentioned. I have tried to include ever possible load I may want to connect but may not be installing say the towel warmers for example.

Bottom line is that I have to try and do this install myself to keep the costs down and make the project feasible.Thanks for mentioning that Dectra did design work,that's what this forum is all about. I may have to look into that as an option.

Thanks very much for your comments. You have made some good points. Scott

 

[Como]

A lot of the Boiler manufacturer web sites have schematics of installs.

My gut feel is that you could save yourself a lot of time and frustration by getting somebody to design it right but this might help.

 

[Como]

http://www.boilerstoves.co.uk/boiler-stove-installation-D.html

A very quick google

 

[Gooserider]

Also hit some of the equipment maker websites - there are lots of free programs to do various calculations and design stuff... Slant-fin used to have a really nice heat load calculator for instance, and Taco seems to have a bunch of different programs - most seem to require you to have a defective OS to operate :sick: but I may try setting up a standalone box and sneaker-netting the stuff back and forth to check them out... (I'm not about to put a Microsoft malware box on the house network...) Some of the sketches folks have posted lately appear to have been done with the Taco software which looks like it does a pretty good job...

Obviously they will try to sell their particular brand of product, but the numbers don't change...

Gooserider