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			<title>Green Building Forum - MVHR filters and traffic pollution</title>
			<lastBuildDate>Wed, 09 Sep 2026 00:08:13 +0100</lastBuildDate>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246209#Comment_246209</link>
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		<pubDate>Thu, 25 Aug 2016 17:54:19 +0100</pubDate>
		<author>Swarm</author>
		<description>
			<![CDATA[I've only had my MVHR running for a few months and noticed that one of the filters is very dark grey, rather than the white it was. The MVHR vents are about 10m up on the outside of the house and about 5m horizontally from a road that's not that busy. Although we do have a bus stop outside... :(<br /><br />Has anyone else experienced traffic pollution on their filters? It makes me wonder what is getting past the filters...<br /><br />Also, is it normal for a lot of water to be in the heat exchanger, I pulled it out to check it over and got a shock when water started spilling out!<br /><br />Lastly, as mentioned in another topic, I'm getting quite a lot of fruit flies and the odd fly + month loitering in the unit too. Just concerned something may not be set up correctly as I have no previous experience of MVHR.]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246210#Comment_246210</link>
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		<pubDate>Thu, 25 Aug 2016 18:00:09 +0100</pubDate>
		<author>DarylP</author>
		<description>
			<![CDATA[The bus-stop will probably be the problem (more specifically the decelerating/accelerating buses!)....<br />There should be a condensate trap in the MVHR unit, is it blocked? Or is the MVHR unit correctly orientated?<br />Cheers <img src="/newforum/extensions/Vanillacons/smilies/standard/smile.gif" alt=":smile:" title=":smile:" />]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246211#Comment_246211</link>
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		<pubDate>Thu, 25 Aug 2016 18:16:52 +0100</pubDate>
		<author>CWatters</author>
		<description>
			<![CDATA[I'm in a rural location and was surprised how fast the filters in our MVHR get dirty. Virtually blocked in less than 6 months.<br /><br />As Daryl said, there should be a condensation drain pipe on the heat exchanger although I've never actually seen water coming out of mine.]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246213#Comment_246213</link>
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		<pubDate>Thu, 25 Aug 2016 18:38:15 +0100</pubDate>
		<author>Swarm</author>
		<description>
			<![CDATA[Thanks for your replies. Yes there's a drain pipe from the unit and I could see a tiny trickle of water down the built-in duct going down to it inside the unit. This tiny trickle didn't bear any relation to the quantity of water that seemed to be in the HE though. <br /><br />I couldn't visibly see what's left inside but probably about 100ml leaked out when I tilted the HE and it seemed weightier than it should be. It's a very damp and rainy day today, so that's probably it and maybe it just takes a long time for the water to trickle out.<br /><br />It's got me a bit worried about standing water in a warm environment though, legionnaires?!]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246216#Comment_246216</link>
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		<pubDate>Thu, 25 Aug 2016 19:03:57 +0100</pubDate>
		<author>Nick Parsons</author>
		<description>
			<![CDATA['' I'm getting quite a lot of fruit flies and the odd (fly +) month loitering in the unit too''<br /><br />What, February?<br /><br /><img src="/newforum/extensions/Vanillacons/smilies/standard/bigsmile.gif" alt=":bigsmile:" title=":bigsmile:" /><img src="/newforum/extensions/Vanillacons/smilies/standard/bigsmile.gif" alt=":bigsmile:" title=":bigsmile:" />]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246217#Comment_246217</link>
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		<pubDate>Thu, 25 Aug 2016 19:11:52 +0100</pubDate>
		<author>Swarm</author>
		<description>
			<![CDATA[Flybruary!]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246224#Comment_246224</link>
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		<pubDate>Thu, 25 Aug 2016 20:44:18 +0100</pubDate>
		<author>Nick Parsons</author>
		<description>
			<![CDATA[Where flies read books....]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246231#Comment_246231</link>
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		<pubDate>Thu, 25 Aug 2016 22:40:07 +0100</pubDate>
		<author>snyggapa</author>
		<description>
			<![CDATA[We're rural and the filters turn to thick grey in a few months...]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246238#Comment_246238</link>
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		<pubDate>Thu, 25 Aug 2016 23:43:23 +0100</pubDate>
		<author>djh</author>
		<description>
			<![CDATA[A 'few' months covers a multitude of sins. And there are many different types of filter. I clean our G4 intake filter every 'few' months because of dust in a rural location.<br /><br />I don't think there should be any appreciable amount of water in the heat exchanger. I would get it checked by the installer.]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246243#Comment_246243</link>
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		<pubDate>Fri, 26 Aug 2016 00:12:00 +0100</pubDate>
		<author>EasyBuilder</author>
		<description>
			<![CDATA[The water condenses in the heat exchanger core. Depending upon the orientation of the core in the MVHR unit the water may not all run out but just sit there until it evaporates. If you tilt a unit of this design then lots of water will run out. Would be interesting to know the make and model.]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246247#Comment_246247</link>
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		<pubDate>Fri, 26 Aug 2016 07:40:28 +0100</pubDate>
		<author>Swarm</author>
		<description>
			<![CDATA[It is a Vent Axia Kinetic plus with humidistat and summer bypass. I will email the installer...]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246268#Comment_246268</link>
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		<pubDate>Fri, 26 Aug 2016 10:58:34 +0100</pubDate>
		<author>snyggapa</author>
		<description>
			<![CDATA[:D "few" is about three months in my case. When the unit  nags me, anyhow.<br /><br />With regards to collecting water, the vent axia condensate drain is pretty simple - I'd take the front panel off (6 screws from memory) and take a look - I would expect maybe some "uphill pipework" to be the culprit. <br /><br />You can look in the manual or online to see how it's mean to work but basically there is an outlet at the bottom that you connect to a pipe. Sounds like either the unit is not level so water is pooling at one end, or the outlet pipe has an uphill bit  which causes the same effect.]]>
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		<title>MVHR filters and traffic pollution</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14493&amp;Focus=246314#Comment_246314</link>
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		<pubDate>Fri, 26 Aug 2016 22:35:24 +0100</pubDate>
		<author>EasyBuilder</author>
		<description>
			<![CDATA[Yes, the Vent Axia Kinetic Plus has the heat exchanger aligned such that part of the airflow is horizontal and so gravity will not be assisting the condensate to run out. Contrast this with the Itho Advance or HRU Eco 4 where the core sits on an edge rather than on a side so that the outgoing air is flowing down and both airflow and gravity clear the condensate.<br /><br />Kinetic Plus shown here on page 12: http://www.vent-axia.com/files/pdf-downloads/439817Q_4.pdf<br /><br />Eco 4 shown here on page 10: https://www.heatraesadia.com/literature/installation-manuals/HRU-Eco-4-installation-manual.pdf<br /><br />With the Kinetic Plus alignment of the heat exchanger there will be more condensate sitting in the heat exchanger that will run out when the unit is tipped over a little.]]>
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