Hydronic heating and hot water install
Printed From: myHanse.com
Category: Hints & Tips
Forum Name: 370 / 375
Forum Description: 370 / 375 Hints, Tips and News
URL: https://www.myhanse.com/forum_posts.asp?TID=14988
Printed Date: 27 March 2026 at 03:41
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Topic: Hydronic heating and hot water install
Posted By: pearson.henry2
Subject: Hydronic heating and hot water install
Date Posted: 13 February 2025 at 00:05
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Hanse 370 - eberspacher hydronic (D5WSC) installation
We've almost completed this winters main project of getting a hydronic heating system installed. We acquired a used (2008) eberspacher unit which we reconditioned (new seals, filters etc). New 30L twin coil calorifier relocated to the "garage" aft. 15mm PEX pipe run to 3 heater matrix units: One for two aft cabins, one dedicate to heads and one for saloon/fwd cabin (2 outlets in saloon, one in forepeak). 15mm PEX around boat just has standard domestic foam insulation on. Managed to get some insulation on main hydronic pipes and engines ones to calorifier. For longer runs between fan matrix and outlet also put some cheap foil bubble wrap insulation around them. Control cable ran to Nav station including diagnostic cable to connect unit to PC. Can get old eberspacher Edith software to see internal flame sensor temperature, status, voltages, error codes etc. Added a day tank and fuel transfer pump from main engine tank. Required new 10mm2 cables to be run aft, goes through a 20a fused relay. On main startup can draw 15a but once running goes down to about 4.5a, and about 0.5L of fuel per hour. Also have temp sensors on the pipe work and small (35cm) tank level sender in day tank connected to Victron Cerbo. Also added an accumulator to hot water side of system. Requires a bit of planning but all relatively straightforward. On big tip is on the small fuel pipes use only proper "super clamps" and try both correct size and the size down (size down generally better).  You can see more photos here: https://www.facebook.com/share/p/1GjPPBMSgQ/" rel="nofollow - https://www.facebook.com/share/p/1GjPPBMSgQ/ |
Replies:
Posted By: H8jer
Date Posted: 13 February 2025 at 10:07
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Hi Henry Interesting project. Does it need an expansion tank? And what kind of fluid is used in the pex pipes? Will look forward to hear how it works. Kind regards ------------- Hanse 370#487 30HP 3-cabin |
Posted By: sgrhma2
Date Posted: 13 February 2025 at 18:10
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I did something similar in my 370, but what I did was retain the hot air heater and added a webasto thermo top c/e to give me hot water. I think it’s one of the best additions I’ve made to the boat for living aboard on extended trips. It allows me to have the boat nice and warm and have hot water at the touch of a button when I want it without having to run the engine. If the heater is running for 30 minutes there’s loads of hot water for two people to have a shower and do the dishes. My boat lives on a mooring and it’s a real convenience to get on board and have hot water. I have no issues with the battery power due to having them maintained by solar panels. You’ve done a great job and you’ll find having hot water ‘on tap’ all the time a fantastic improvement in comfort level. Simon
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Posted By: pearson.henry2
Date Posted: 14 February 2025 at 23:36
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Hi Højer, You needs an expansion/header tank for the glycol water circuit. We have it port side, up high - will get a photo tomorrow. We also added an expansion tank to the hot water side of the calorifier.sonce the fresh cold water into the calorifier has a non-return valve, it needs one on the hot side too. The pex is filled with a water/glycol mix. 50/50 water glycol is standard.
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Posted By: H8jer
Date Posted: 15 February 2025 at 20:43
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Thx. Could Simon's version and your version be combined? 1. Heat the cabins 2. Optional switch to heat the hot water tank. Should not intervene (be separated) from the engine coolant circuit ------------- Hanse 370#487 30HP 3-cabin |
Posted By: pearson.henry2
Date Posted: 15 February 2025 at 21:15
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Højer,
The manifold we installed allows us to do exactly that. We have 4 circuits:
The calorifier is dual coil so has heating from:
Here's a photo with the manifold. We also have the header tank with 2 connections and a valve. This is a great setup to easily allow for air removal during initial setup - we run 1 circuit at a time, forcing the return to go via the header tank.   |
Posted By: H8jer
Date Posted: 16 February 2025 at 15:04
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Hi Henry Thx for the explanation. Now I get it. It is because you use a different calorifer/Hot water tank with additional heat exchangers. I use a Calorifier in the "normal" position... https://www.myhanse.com/new-waterheater-needed-now-updated_topic12672_post105163_SID5547-b7d9z8c24d12f87f78df6255092593.html#105163" rel="nofollow - https://www.myhanse.com/new-waterheater-needed-now-updated_topic12672_post105163_SID5547-b7d9z8c24d12f87f78df6255092593.html#105163 ------------- Hanse 370#487 30HP 3-cabin |
Posted By: pearson.henry2
Date Posted: 16 February 2025 at 19:00
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Yes we fitted a new, larger, calorifier and moved it at the same time. The space behind the rudder stock was wasted space and the empty locker is good for storage now. We had seen your photos and reckoned that the calorifier would need replacing soon anyway so now was a good time to upgrade.
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